ALBERT

Description: [1]  Neutron monitors have recorded the flux of high energy Galactic cosmic rays for more than half a century. During the recent prolonged, deep minimum in solar activity many sources indicate that modulated Galactic cosmic rays have attained new space-age highs. However reported neutron monitor rates are ambiguous; some record new highs while others do not. This work examines the record of 15 long-running neutron monitors to evaluate cosmic ray fluxes during the recent extraordinary solar minimum in a long-term context. We show that ground-level neutron rates did reach a historic high during the recent solar minimum, and we present a new analysis of the cosmic ray energy spectrum in the year 2009 versus year 1987. To do this we define a reference as the average of eight high-latitude neutron monitors, four in the northern hemisphere (Apatity, Inuvik, Oulu, Thule) and four in the southern hemisphere (Kerguelen, McMurdo, Sanae, Terre Adelie). Most stations display changes in sensitivity, which we characterize by a simple linear trend. After correcting for the change in sensitivity, a consistent picture emerges. With our correction all stations considered display new highs at the recent solar minimum, approximately 3% above the previous record high. These increases are shown to be consistent with spacecraft observations.

Description: [1]  We present the occurrence frequency of downgoing auroral electron beams in magnetic local time and invariant latitude, and the dependence on solar cycle, as indicated by F10.7, on whether the ionospheric footpoint of the satellite is illuminated or dark, and on the energy flux carried by the electrons. As previously reported, we find that the occurrence of electron beams peaks in the pre-midnight local time sector and that solar illumination at the footpoint (solar zenith angle) reduces both the occurrence and energy of the electron beams. The effect of solar maximum conditions (indicated by F10.7) is almost as large as the effect of the solar zenith angle. The characteristic energy of the electron beams is dependent on the energy flux carried, in addition to both solar zenith angle and F10.7. The beam energy (and therefore the parallel potential drop) is ~1.6 times higher for during solar minimum than during solar maximum for both dark and illuminated footpoints. The beam energy during dark solar minimum conditions is a factor of ~3 more than during sunlit minimum conditions. The ‘area’ covered by intense aurora is also reduced during solar maximum, for both sunlit and dark conditions. There is no evidence that the statistical results are due to the fact that acceleration via parallel electric fields moves to lower latitudes during solar maximum.

Description: [1]  In this paper we describe and quantify the energy transfer, flow and distribution. Our high-resolution data-set covers 13 years of OMNI, SuperMAG and Kyoto data. We employ what we consider to be the best estimates for energy sinks, and relate these to SuperMAG indices for better coverage and spatial resolution. For the energy input we have used the method of dimensional analysis [ Vasyliunas et al ., 1982] that is presented in unit power and makes it appropriate for energy analysis. A cross-correlation analysis parameterizes the magnetospheric response on the solar wind parameters during a wide range of conditions, ranging from substorms and storms up to a decade. The determined functional form is then evaluated and scaled using superposed epoch analysis of geomagnetic storms, revealing that the effective area of interaction can not be considered static. Instead we present a dynamic area which depends to the first order on the cube of the IMF B z component. Also, we find that for longer time periods this area must be increased compared to the area used for geomagnetic storms. We argue that some of the terms in the energy coupling function are contributory to describing magnetosheath conditions, and discuss how our coupling function can be related to Maxwell stress components. Also, we quantify the relative importance of the different energy sinks during substorms, geomagnetic storms and long time series, and present the coupling efficiency of the solar wind. Our energy coupling functions is compared with the ɛ parameter [ Akasofu and Perreault , 1978] and performs better for almost any event.

Description: [1]  Plasma sheet flow bursts have been suggested to correspond to different types of auroral activity, such as poleward boundary intensifications (PBIs), ensuing auroral streamers, and substorms. The flow-aurora association leads to the important question of identifying the magnetotail source region for the flow bursts and how this region depends on magnetic activity. The present study uses the ARTEMIS spacecraft coordinated with conjugate ground-based auroral imager observations to identify flow bursts beyond 45 R E downtail and corresponding auroral forms. We find that quiet-time flows are directed dominantly earthward with a one-to-one correspondence with PBIs. Flow bursts during the substorm recovery phase, and during steady magnetospheric convection (SMC) periods are also directed earthward, and these flows are associated with a series of PBIs/streamers lasting for tens of minutes with similar durations to that of the series of earthward flows. Pre-substorm onset flows are also earthward and associated with PBIs/streamers. The earthward flows during those magnetic conditions suggest that the flow bursts, which lead to PBIs and streamers, originate from further downtail of ARTEMIS, possibly from the distant tail neutral line (DNL) or tailward-retreated near-Earth neutral line (NENL) rather than from the nominal NENL location in the mid-tail. We find that tailward flows are limited primarily to the substorm expansion phase. They continue throughout the period of auroral poleward expansion, indicating that the expansion-phase flows originate from the NENL and that NENL activity is closely related to the auroral expansion of the substorm expansion phase.

Description: [1]  The solar eclipse on 15 January 2010 traversed Asia and completed its travel on the Shandong Peninsula in China at sunset. Two vertical-incidence ionosondes at Wuhan and Beijing and the oblique-incidence ionosonde network in North China were implemented to record the ionospheric response to the solar eclipse. Following the initial electron density decrease caused by the eclipse, the ionosphere was characterized by a strong pre-midnight enhancement, and a subsequent ionospheric decay, and a ~10 hour later post-midnight enhancement. Neither geomagnetic disturbance occurred during the eclipse day, nor did obvious nighttime peak appear for the ten-day mean of the F2-layer critical frequency ( fo F2). The electron density profilogram of the Beijing ionosonde indicates that the two enhancements were the result of the plasma flux downward from the top ionosphere, possibly due to the steep decrease of the ionospheric electron density and plasma temperature during the solar eclipse. The two-dimensional differential fo F2 maps present the regional variations of the nighttime electron density peaks and decay. Both the pre- and post-midnight enhancements initially appeared in a belt almost in parallel with the eclipse track and then drifted southward. The different magnitudes of greatest eclipse in the umbra and outside tend to account for the different occurrence times of the plasma flux. The ionospheric decay following the pre-midnight enhancement is also considered as a consequence of the eclipse shade.

Description: [1]  We study a statistics of ∂  B z /∂  x in a thin stretching current sheet (substorm growth phases) observed by Cluster between 8 and 18 R E downtail. After 2005 spacecraft separation allowed to measure directly this derivative of B z along the tail axis. The near-tail events (within 14 R E ) exhibited a straight decrease of an initially large positive ∂  B z /∂  x to ∼ 1–2 nT/ R E . In the more stretched middle tail, usually the small | ∂  B z /∂  x | 〈 0.5 − 1 nT/ R E had no clear trend and fluctuated around zero with time scales 5–15 min. In general, negative ∂  B z /∂  x were ubiquitous. At some onsets larger negative ∂  B z /∂  x  〈 − 1 nT/ R E were associated with transient dipolarizations, propagating Earthward. There was no clear association of local plasma sheet activity onset with any value of ∂  B z /∂  x . We discuss relation of observations and recent modeling results.

Description: The reactions of As 2 O 3 , SbCl 3 , and (BiO) 2 CO 3 with oleum (65 % SO 3 ) yielded single crystals of As(S 2 O 7 )(HS 2 O 7 ) [monoclinic, P 2 1 / c , Z = 4, a = 16.549(1), b = 6.6743(5), c = 9.9498(6) Å, β = 102.672(8)°, V = 1072.672(8) Å 3 ], Sb 2 (SO 4 ) 2 (S 2 O 7 ) [monoclinic, P 2 1 / n , Z = 4, a = 9.1586(2), b = 6.9981(2), c = 17.7956(4) Å, β = 100.9690(8)°, V = 1119.73(5) Å 3 ], and Bi 2 (S 2 O 7 ) 3 [triclinic, P , Z = 2, a = 6.5734(1), b = 10.1954(2), c = 11.5121(2) Å, α = 90.996(1)°, β = 96.976(1)°, γ = 94.870(1)°, V = 762.75(2) Å 3 ]. As(S 2 O 7 )(HS 2 O 7 ) shows the arsenic atoms in a trigonal pyramidal coordination of the oxygen atoms of one chelating S 2 O 7 2– and one monodentate HS 2 O 7 – group. The distinct As(S 2 O 7 )(HS 2 O 7 ) molecules are connected with each other by hydrogen bonds to form layers. Sb 2 (SO 4 ) 2 (S 2 O 7 ) shows the Sb 3+ cations in a seesaw-type coordination of oxygen atoms from both anions. In Bi 2 (S 2 O 7 ) 3 the Bi 3+ cations are in a square prismatic oxygen coordination of disulfate units. The antimony and the bismuth compounds exhibit complex three-dimensionally linked structures. The syntheses and the crystal structures, as well as the thermal decomposition of Sb 2 (SO 4 ) 2 (S 2 O 7 ) are presented.

Description: Silver acetate AgOAc reacts with dry liquid ammonia under the formation of colorless needle-shaped crystals of diammine silver(I) acetate [Ag(NH 3 ) 2 ]OAc ( 1 ). The compound crystallizes in the monoclinic space group P 2 1 / c with a = 8.0205(2), b = 12.4161(3), c = 6.0938(2) Å, β = 107.741(4)°, and V = 577.98(3) Å 3 at 123 K with Z = 4. The crystal structure shows the presence of almost linear [Ag(NH 3 ) 2 ] + cations, which are arranged in a corrugated chain of equidistant silver atoms. The Ag–Ag distance is 3.1089(11) Å, which falls in the range of “argentophilic” interactions. After warming to room temperature and removal of the solvent, compound 1 was found unchanged as evidenced by powder X-ray diffraction, thermogravimetric and mass-spectrometric analysis, as well as IR and Raman spectroscopy.

Description: A series of chalcogenidoantimonates, namely [Zn(NH 3 ) 6 ](Sb III 4 S 7 ) ( 1 ), [Zn(NH 3 ) 6 ]{Zn(NH 3 ) 3 Sb V S 4 } 2 · NH 3 ( 2 ), [Mn(NH 3 ) 6 ](Sb III Se 2 ) 2 ( 3 ) and [Zn(NH 3 ) 4 ]{Zn(NH 3 )Sb III Se 3 } 2 · 3NH 3 ( 4 ) are synthesized by solvothermal technique in liquid ammonia at 50 °C from elemental zinc or manganese, antimony and sulfur or selenium. 1 (space group P ) and 2 ( P ) crystallize centrosymmetrically, whereas 3 ( Pna 2 1 ) and 4 ( P 2 1 ) represent polar structures. All compounds contain discrete cationic [Zn(NH 3 ) 4 ] 2+ , [Zn(NH 3 ) 6 ] 2+ , and [Mn(NH 3 ) 6 ] 2+ ammine complexes. In the anionic structure parts, corner-connected trigonal-pyramidal SbS 3 and SbSe 3 are the characteristic building units. 1 and 4 contain 2D polymeric anions, in the latter case with Zn 2+ cations incorporated in a selenidoantimonate(III) network. The polymeric anion in the structure of 3 is a helical chain. 2 is a molecular compound and contains dinuclear anions [S 3 Sb–S–Zn(NH 3 ) 3 ] 2– with Sb V . Raman measurements show the Sb–Ch valence vibrations in the expected region between 250–370 cm –1 for 1 and at 212 cm –1 for 4 . According to the reflectance spectrum 4 is a semiconductor with an optical band gap of 2.05(5) eV.

Description: [1]  ELF/VLF radio waves are difficult to generate with conventional antennas. Ionospheric HF heating facilities generate ELF/VLF waves via modulated heating of the lower ionosphere. HF heating of the ionosphere changes the lower ionospheric conductivity, which in the presence of natural currents such as the auroral electrojet, creates an antenna in the sky when heating is modulated at ELF/VLF frequencies. We present a summary of nearly 100 days of ELF/VLF wave generation experiments at the 3.6 MW HAARP facility near Gakona, Alaska, and provide a baseline reference of ELF/VLF generation capabilities with HF heating. Between February 2007 and August 2008, HAARP was operated on close to 100 days for ELF/VLF wave generation experiments, at a variety of ELF/VLF frequencies, seasons and times of day. We present comprehensive statistics of generated ELF/VLF magnetic fields observed at a nearby site, in the 500-3500 Hz band. Transmissions with a specific HF beam configuration (3.25 MHz, vertical beam, amplitude modulation) are isolated so the data comparison is self-consistent, across nearly 5 million individual measurements of either a tone or a piece of a frequency-time ramp. There is a minimum in the average generation close to local midnight. It is found that generation during local nighttime is on average weaker, but more highly variable, with a small number of very strong generation periods. Signal amplitudes from day to day may vary by as much as 20-30 dB. Generation strengthens by ~5 dB during the first ~30 minutes of transmission, which may be a signature of slow electron density changes from sustained HF heating. Theoretical calculations are made to relate the amplitude observed to the power injected into the waveguide and reaching250 km. The median power generated by HAARP and injected into the waveguide is ~0.05-0.1 W in this base-line configuration (vertical beam, 3.25 MHz, amplitude modulation), but may have generated hundreds of Watts for brief durations. Several efficiency improvements have improved the ELF/VLF wave generation efficiency further.

Description: [1]  An inversion technique for estimating the properties of the magnetospheric plasma from the harmonic frequencies of the toroidal standing Alfvén waves has been used to derive the global equatorial mass density covering radial distances from 4 to 9 Earth radii ( R E ), within the local time sector spanning from 0300 to 1900 hours. This broad range of L shell extending to the outer magnetosphere allows us to examine the local time and radial dependence of the quiet-time equatorial mass density during solar minimum and thereby construct a global distribution of the equatorial mass density. The toroidal Alfvén waves were detected with magnetometers on the Active Magnetospheric Particle Tracer Explorers (AMPTE)/Charge Composition Explorer (CCE) during the nearly 5 year interval from August 1984 to January 1989 and on the Geostationary Operational Environmental Satellites (GOES) (10, 11 and 12) for 2 years from 2007 to 2008, both of which were operating during solar minimum years. The derived equatorial mass density, ρ eq , at geosynchronous orbit (GEO) monotonically increases with increasing magnetic local time (MLT) from the nightside towards the dusk sector. At other radial distances, ρ eq has the same MLT variation as that of GEO, while the magnitude logarithmically decreases with increasing L value. An investigation of the Dst and Kp dependence shows that the median value of ρ eq varies little in the daytime sector during moderately disturbed times, which agrees with previous studies. ρ eq calculated from the F 10.7 dependent empirical model shows good agreement with that of CCE but overestimates that of GOES probably due to the extreme solar cycle minimum in years 2007–2008.

Description: [1]  In this paper we compare observations of the high latitude cusp from DMSP data to simulations conducted using the Lyon-Fedder-Mobarry (LFM) global magnetosphere simulation. The LFM simulation is run for the 31 Aug 2005 to 02 Sep 2005 moderate storm, from which the solar wind data exhibits a wide range of conditions that enable a statistical representation of the cusp to be obtained. The location of the cusp is identified using traditional magnetic depression and plasma density enhancement at high altitude. A new diagnostic using the parallel ion number flux is also tested for cusp identification. The correlation of the cusp latitude and various solar wind IMF coupling functions is explored using the three different cusp identification methods. The analysis shows 1) the three methods give approximately the same location and size of the simulated cusp at high altitude; 2) the variations of the simulated cusp are remarkably consistent with the observed statistical variations of the low-altitude cusp. In agreement with observations a higher correlation is obtained using other solar wind coupling functions such as the Kan-Lee electric field. The MLT position of the simulated cusp is found to depend upon the IMF By component, with a lower linear correlation. The width of the simulated cusp in both latitude and MLT is also examined. The size of the cusp is found to increase with the solar wind dynamic pressure with saturation seen when the dynamic pressure is greater than 3 nPa.

Description: [1]  Daily profiles of phase measurements as observed on fixed VLF-paths generally show a transient phase advance, followed by a phase delay, for about 90 minutes after sunrise hours. This is indicative of a reflecting ionospheric C-region developing along the terminator line at an altitude below the normal D-region. The suggested occurrence of a C-region is consistent with rocket measurements made in the 1960's, showing a maximum of the electron density between 64 and 68 km, and by radio sounding in the 1980's. In order to correctly describe the properties of the phase effect associated with the presence of a C-region, it is important to understand the subionospheric propagation characteristics of the VLF-paths. In this paper, we analyze the variations presented by the temporal properties of the VLF narrow-band phase effect, and determined a parameter associated with the appearance of the C-region at sunrise hours observed by receivers from the South America VLF Network (SAVNET). Periodic patterns emerge from the parameter curves. Two distinct temporal behavior regimes can be identified: one exhibiting slow variations between March and October, and another one exhibiting faster variations between October and March. Solar illumination conditions and the geometrical configuration of the VLF paths relative to the sunrise terminator partly explain the slow variation regime. During periods of faster variations, we have observed good association with atmospheric temperature variability found in the measurements of the TIMED-SABER satellite instrument, which we assume to be related to the Winter Anomaly atmospheric phenomenon. However, when comparing the parameter time series with temperature curves, no direct one-to-one correspondence was found for transient events.

Description: [1]  On 21 January 2005, one of the fastest interplanetary coronal mass ejections (ICME) of solar cycle 23, containing exceptionally dense plasma directly behind the sheath, hit the magnetosphere. We show from charge-state analysis that this material was a piece of the erupting solar filament, and further, based on comparisons to the simulation of a fast CME, that the unusual location of the filament material was a consequence of three processes. As the ICME decelerated, the momentum of the dense filament material caused it to push through the flux rope towards the nose. Diverging non-radial flows in front of the filament moved magnetic flux to the sides of the ICME. At the same time reconnection between the leading edge of the ICME and the sheath magnetic fields worked to peel away the outer layers of the flux rope creating a remnant flux rope and a trailing region of newly opened magnetic field lines. These processes combined to move the filament material into direct contact with the ICME sheath region. Within one hour after impact and under northward IMF conditions, a cold dense plasma sheet formed within the magnetosphere from the filament material. Dense plasma sheet material continued to move through the magnetosphere for more than 6 hours as the filament passed by the Earth. Densities were high enough to produce strong diamagnetic stretching of the magnetotail despite the northward IMF conditions and low levels of magnetic activity. The disruptions from the filament collision are linked to an array of unusual features throughout the magnetosphere, ionosphere and atmosphere. These results raise questions about whether rare collisions with solar filaments may, under the right conditions, be a factor in producing even more extreme events.

Description: [1]  We present observations from the Falkland Islands SuperDARN radar of the propagation of HF radio waves via the Weddell Sea ionospheric Anomaly (WSA), a region of enhanced austral summer nighttime ionospheric electron densities covering the southern Pacific and South Americas region. This anomaly is thought to be produced by uplift of the ionosphere by prevailing equatorwards thermospheric winds. Of particular interest are perturbations of the WSA-supported propagation, which suggest that during periods of geomagnetic disturbance the ionospheric layer can be lowered by several 10s of km and subsequently recover over a period of 1 to 2 hours. Perturbations can appear singly or as a train of 2 to 3 events. We discuss possible causes of the perturbations, and conclude that they are associated with equatorward-propagating large-scale atmospheric waves produced by magnetospheric energy deposition in the auroral or sub-auroral ionosphere. Changes in high/mid-latitude electrodynamics during geomagnetic storms may also account for the perturbations, but further modeling is required to fully understand their cause.

Description: [1]  Inner magnetosphere magnetic field and plasma flow data are examined during 228 steady magnetospheric convection events. We find that the B Z component of the magnetic field around geostationary orbit is weaker than during average conditions and the plasma flow speeds are higher than average in the dusk sector just beyond geostationary orbit. The SMC periods include more enhanced Earthward and tailward flow intervals than during average conditions. The steady convection period magnetic field is not steady: The near-geostationary nightside field grows increasingly taillike throughout the steady convection period. In the midtail, Earthward flows are enhanced in a wide region around the midnight sector, which leads to enhanced magnetic flux transport toward the Earth during the steady convection periods. Compared to well-known characteristics during magnetospheric substorms, the inner tail evolution resembles that during the substorm growth phase, while the midtail flow characteristics duringsteady convection periods are similar to those found during substorm recovery phases.

Description: . Sr 2 CoOsO 6 , a new osmium based ordered semiconductor double perovskite was prepared by solid state synthesis from the respective binary oxides. Room temperature PXRD analysis shows the compound to be tetragonal [ I 4/ m ; a = 5.5503(1) Å and c = 7.9320(1) Å], whereas low temperature synchrotron data refinement has revealed a second monoclinic polymorph [ I 2/ m ; a = 5.4969(2) Å, b = 5.4979(2) Å, c = 8.0090(1) Å and γ = 90.527(1)°] with a fully ordered rocksalt arrangement of cobalt and osmium atoms over the perovskite B -sites. Heat capacity and magnetic measurements indicate that Sr 2 CoOsO 6 shows antiferromagnetic ordering below T N = 108 K followed by a second magnetic transition at T 2 = 65 K. It was shown that the change from the tetragonal to the monoclinic phase occurs at T N .

Description: . The ternary germanides RE Rh 6 Ge 4 ( RE = Y, La, Pr, Nd, Sm–Lu) were obtained by arc-melting of the elements and subsequent annealing. Single crystals were grown from bismuth fluxes. The samples were studied by X-ray diffraction on powders. The structures of five members were refined from single crystal diffraction data: LiCo 6 P 4 type, P m 2, a = 715.8(1), c = 387.33(8) pm, wR = 0.0238, 332 F 2 values for LaRh 6 Ge 4 , a = 715.0(1), c = 384.96(7) pm, wR = 0.0211, 329 F 2 values for PrRh 6 Ge 4 , a = 714.28(9), c = 382.57(6) pm, wR = 0.0136, 327 F 2 values for SmRh 6 Ge 4 , a = 714.2(1), c = 381.6(1), wR = 0.0270, 327 F 2 values for GdRh 6 Ge 4 , and a = 714.2(2), c = 379.0(1) pm, wR = 0.0273, 324 F 2 values for HoRh 6 Ge 4 with 19 variables per refinement. The RE Rh 6 Ge 4 structures have two crystallographically independent germanium sites in trigonal prismatic coordination, manifesting the close structural relationship with metal-rich phosphides. Together, the rhodium and germanium atoms build up three-dimensional [Rh 6 Ge 4 ] networks, which leave large channels for the rare earth atoms. Each rare earth atom has coordination number 20 with 12 Rh, 6 Ge, and 2 RE neighbors. Temperature dependent magnetic susceptibility measurements indicate Pauli paramagnetic behavior for YRh 6 Ge 4 , LaRh 6 Ge 4 , and LuRh 6 Ge 4 . The compounds RE Rh 6 Ge 4 ( RE = Gd–Yb) are Curie-Weiss paramagnets. Antiferromagnetic ordering was observed at 8.4(5) K (GdRh 6 Ge 4 ), 13.6(5) K (TbRh 6 Ge 4 ), 5.1(5) K (DyRh 6 Ge 4 ), and 8.9(5) K (YbRh 6 Ge 4 ). DyRh 6 Ge 4 and YbRh 6 Ge 4 show metamagnetic transitions at 2.5(5) and 45(2) kOe, respectively.

Description: Reaction of manganese(II) thiocyanate with 2-chloropyrazine leads always to the formation of a compound of composition Mn(NCS) 2 (2-chloropyrazine) 4 ( 1 - Mn/Cl ) that consists of discrete complexes, in which the manganese cation is coordinated by two terminal thiocyanato anions and four 2-chloropyrazine ligands. In contrast, with 2-methylpyrazine only an aqua complex of composition Mn(NCS) 2 (2-methylpyrazine) 2 (H 2 O) 2 ( 1 - Mn/CH 3 ) is obtained that also consists of discrete octahedrally coordinated complexes. Moreover, a few single crystals of Mn(NCS) 2 (2-chloropyrazine) 4 · Mn(NCS) 2 (2-chloropyrazine) 2 (H 2 O) 2 · 2-chloropyrazine trisolvate ( 2 - Mn/Cl ) and Mn(NCS) 2 (2-methylpyrazine) 2 (H 2 O) 2 · Mn(NCS) 2 (H 2 O) 4 ( 2 - Mn/CH 3 ) were accidently obtained but no larger amounts are available. On heating, 1 - Mn/Cl and 1 - Mn/CH 3 transforms into new compounds of composition Mn(NCS) 2 (L) 2 (L = 2-chloropyrazine) ( 4 - Mn/Cl ) and 2-methylpyrazine ( 3 - Mn/CH 3 ). Surprisingly on further heating 1 - Mn/CH 3 looses additional 2-methylpyrazine ligands and transforms into a new compound of composition Mn(NCS) 2 (2-methylpyrazine) ( 4 - Mn/CH 3 ). Compound 4 - Mn/Cl is isotypic to its cobalt(II) analog and 4 - Mn/CH 3 is isotypic to Cd(NCS) 2 (2-methylpyrazine) reported recently and therefore, both structures were refined by the Rietveld method. The crystal structures of both compounds are strongly related. They consists of dimeric units, in which each two manganese cations are linked by pairs of μ-1,3-bridging thiocyanato anions, which are further connected into layers by single μ-1, 3-bridging anionic ligands. In contrast to 4 - Mn/Cl , in 4 - Mn/CH 3 these layers are further linked into a 3D coordination network by the 2-methylpyrazine ligands. Magnetic measurements reveal that 1 - Mn/Cl , 1 - Mn/CH 3 , and 3 - Mn/CH 3 shows only Curie- or Curie-Weiss paramagnetism, whereas 4 - Mn/Cl and 4 - Mn/CH 3 shows antiferromagnetic ordering at T N = 22.9 K and at 26.5 K. The results of these investigations are compared with those obtained for related compounds.

Description: . Black platelets of Bi 39.67(7) Ru 2 Br 35.0(2) were crystallized from a melt of Bi, BiBr 3 , and Ru. In the tetragonal crystal structure [ P 4/ mbm , a = 1311.92(6) pm, c = 3018.2(4) pm at 155(5) K], cluster cations [(Bi 8 2+ )Ru 2+ (Bi 8 2+ )] are embedded in a matrix of disordered bromido-bismuthate(III) groups. A thorough analysis of the disorder in the anionic part enabled the unambiguous assignment of the cluster charge. The η 4 -coordination of the two Bi 8 2+ square antiprisms to the Ru II atom in the sandwich complex resembles the bonding of Bi 5 + and Bi 8 2+ in the clusters [(Bi 5 + )Ru + (Bi 4 Br 4 )Ru + (Bi 5 + )] and [(Bi 8 2+ )Ru + (Bi 4 Br 4 )Ru + (Bi 5 + )] as well as of Bi 4 2– in 1 ∞ [(Bi 4 2– )Ru + (Bi 4 Br 4 )Ru + ]. By combining crystal chemical considerations for all mentioned compounds and using quantum chemical calculations, a common bonding scheme for the coordination compounds of bismuth polycations and polyanions was established. The η 4 -coordinating bismuth polycations and polyanions act as six electron donors, comparable to nido -carborane ligands, Zintl anions E 9 4– and E 5 6– ( E = Si to Pb), cyclopentadienyl ligands, or the cyclobutadiene dianion. The electron count for the transition metal is 18 in all finite clusters.

Description: [1]  A global total electron content (TEC) model response to geomagnetic activity described by the K p -index is built by using the Center for Orbit Determination of Europe (CODE) TEC data for full 13 years, January 1999 - December 2011. The model describes the most probable spatial distribution and temporal variability of the geomagnetically forced TEC anomalies assuming that these anomalies at a given modip latitude depend mainly on the K p -index, local time (LT) and longitude. The geomagnetic anomalies are expressed by the relative deviation of TEC from its 15-day median and are denoted as rTEC. The rTEC response to the geomagnetic activity is presented by a sum of two responses with different time delay constants and different sign of the cross-correlation function. It has been found that the mean dependence of rTEC on K p -index can be expressed by a cubic function. The LT dependence of rTEC is described by Fourier time series which includes the contribution of four diurnal components with periods 24, 12, 8 and 6 hours. The rTEC dependence on longitude is presented by Fourier series which includes the contribution of zonal waves with zonal wavenumbers up to 6. In order to demonstrate how the model is able to reproduce the rTEC response to geomagnetic activity three geomagnetic storms at different seasons and solar activity conditions are presented. The model residuals clearly reveal two types of the model deviation from the data: some underestimation of the largest TEC response to the geomagnetic activity and randomly distributed errors which are the data noise or anomalies generated by other sources. The presented TEC model fits to the CODE TEC input data with small negative bias of -0.204, root mean squares error RMSE  = 4.592 and standard deviation error STDE  = 4.588. The model offers TEC maps which depend on geographic coordinates (5 o x5 o in latitude and longitude), and universal time (UT) at given geomagnetic activity and day of the year. It could be used for both science and possible service (nowcasting and short-term prediction); for the latter a detailed validation of the model at different geophysical conditions has to be performed in order to clarify the model predicting quality.

Description: [1]  Magnetic reconnection (MR), a fundamental process in space plasmas that changes magnetic topology and converts magnetic energy into kinetic and thermal energies, is an ultimate driver of space weather. There exist two models of MR in the literatures, anti-parallel and component, associated with intensive studies of their generation and applications. In this paper we report an MR event observed by Cluster constellation in the geo-magnetotail where both types of MR were detected. By reconstructing the three-dimensional (3D) MR configuration we find that a pair of A-B nulls existed in both types of MR cases with two fan surfaces intersecting each other to form a separator line connecting the nulls. A weak or sizable magnetic field exists along the separator in the anti-parallel or component case, respectively. In the latter case, field strength is finite away from the two nulls and vanishes close to the nulls. Therefore, at least in the two cases observed, both anti-parallel and component MR geometries are local presentation of the separator MR configuration. This result supports the expectation that 3D nulls often occur as a crucial element of MR at least in the magnetotail and separator MR may play an important role in dynamics and reconfiguration of magnetic field in 3D MR processes.

Description: [1]  The development of equatorial plasma irregularity plumes can be well recorded by steerable backscatter radars operated at and off the magnetic equator due to the fact that the vertically extended plume structures are tracers of magnetically north-south aligned larger scale structures. From observations during March 2012, using two low latitude steerable backscatter radars in Southeast Asia, the Equatorial Atmosphere Radar (EAR) (0.2ºS, 100.3ºE; dip lat 10.4ºS) and the Sanya VHF radar (18.4ºN, 109.6ºE; dip lat 12.8ºN), the characteristics of backscatter plumes over the two sites separated in longitude by ~1000 km were simultaneously investigated. The beam steering measurements reveal frequent occurrences of multiple plumes over both radar sites, of which two cases are analyzed here. The observations on 30 March 2012 show plume structures initiated within the radar scanned area, followed by others drifting from the west of the radar beam over both stations. A tracing analysis on the onset locations of plasma plumes reveals spatially well-separated backscatter plumes, with a maximum east-west wavelength of about 1000 km, periodically generated in longitudes between 85ºE and 110ºE. The post-sunset backscatter plumes seen by the Sanya VHF radar are found to be due to the passage of sunset plumes initiated around the longitude of EAR. Most interestingly, the EAR measurements on the night of 21 March 2012 show multiple plume structures that developed successively in the radar scanned area with east-west separation of ~50 km, with however, no sunset plasma plume over Sanya. Co-located ionogram measurements show that spread F irregularities occurred mainly in the bottomside F-region at Sanya, whereas satellite traces in ionograms that are indications of large-scale wave structures, were observed on that night at both stations. Possible causes for the longitudinal difference in the characteristics of radar backscatter plumes are discussed.

Description: . Previous attempts to synthesize and isolate (thiobisphenolate) vanadium(V) dioxido complexes had always provided their dimers containing [O=V(μ-O) 2 V=O] 2+ cores, and these also dominate the solution reactivity. Hence, the behavior of their parent monomers, which represent the major species in solution, has remained uncertain. Herein we report the development of a synthetic route that allowed for the successful isolation, spectroscopic investigation, and structural characterization of the monomer PPh 4 [ S LVO 2 ] ( 3 ) [ S L 2– = 2′2-thiobis(2, 4-di- tert -butylphenolate)]. For this purpose PPh 4 [ S LVOCl 2 ] ( 1 ) had to be accessed first in order to convert it to the ethoxido compound PPh 4 [ S LVO(OEt) 2 ] ( 2 ), which is more prone to hydrolysis. Treatment of 2 with stoichiometric amounts of water followed by immediate cooling to –30 °C led to crystals of 3 . After its dissolution NMR spectra were recorded that were identical with those obtained after dissolution of its dimer, thus confirming the monomer/dimer equilibrium postulated previously. The molecular structure of 3 revealed the absence of a V ··· S interaction, which, however, stabilizes its dimer, and thus suggested the employment of a bisphenolate ligand lacking a bridging sulfur atom to obtain an analogue, which does not undergo dimerization in solution. In Et L 2– the sulfur atom is replaced by an ethylmethine unit and indeed the corresponding complex NBu 4 [ Et LVO 2 ] ( 4 ) proved to be stable as a monomer. Investigation of its potential as a catalyst for the oxidative dehydrogenation of 9-fluorenol confirmed a much lower reactivity in comparison to dimeric complexes, which is discussed.

Description: Two complexes, cis -[MnL 2 (NCS) 2 ] ( 1 ) and cis -[ZnL 2 (NCS) 2 ] ( 2 ) with asymmetrical substituted triazole ligands [L = 3, 4-dimethyl-5-(2-pyridyl)-1, 2, 4-triazole], were synthesized and characterized by elemental analysis, UV/Vis and FT-IR spectroscopy as well as thermogravimetric analyses (TGA), powder XRD, and single-crystal X-ray diffraction. In the complexes, each L molecule adopts a chelating bidentate mode by the nitrogen atoms of pyridyl and triazole. Both complexes have a similar distorted octahedral [ M N 6 ] core ( M = Mn 2+ and Zn 2+ ) with two NCS – ions in the cis position.

Description: . The multi-shaped amorphous alloy (Ni-B) powders were prepared by complexing reduction route using sodium borohydride (NaBH 4 ) as reductant with assistance of ultrasonic wave. The selected complexants, i.e. water, ammonia, salicylic acid, and ethylene diamine tetraacetic acid (EDTA) possess sequentially escalating complexation ability. The chemical composition and shapes of the product samples obtained under different conditions were characterized by X-ray powder differaction, selected area electron diffraction, and transmission electron microscope. The influence of reaction conditions such as the types of Ni-B, temperatures, NaBH 4 concentrations, and sodium hydroxide (NaOH) content on the hydrogen generation rate of hydrolysis of NaBH 4 solution were investigated in detail. The results show that the as-prepared Ni-B powders all belong to amorphous alloy with variable element contents, and the Ni-B sample prepared from EDTA complexation, possessing the best fineness and dispersity, has the strongest catalytic activity. The mean apparent activation energy of the hydrolysis reaction is 64.90 kJ · mol –1 . The NaBH 4 concentration has little impact on hydrogen generation rate, implying that the catalytic hydrolysis of NaBH 4 solution should be the pseudo zero-order reaction. Keeping the NaOH content at below 5 % could inhibit the hydrolysis of NaBH 4 solution, but the NaOH contents from 10 % to 15 % will significantly promote the hydrolysis rate of NaBH 4 . The hydrolysis reaction mechanisms, especially the effect of NaOH content on the hydrolysis reaction were also analyzed.

Description: [1]  The solar wind impacting the Earth varies over a wide range of time scales, driving a corresponding range of geomagnetic activity. Past work has strongly indicated the rate of merging on the frontside magnetosphere is the most important predictor for magnetospheric activity, especially over a few hours. However the magnetosphere exhibits variations on other time scales, including UT, seasonal, and solar cycle variations. Much of this geomagnetic variation cannot be reasonably attributed to changes in the solar wind driving – that is, it is not created by the original Russell-McPherron effect or any generalization thereof. In this paper we examine the solar cycle, seasonal, and diurnal effects based upon the frequency of substorm onsets, using a data set of 53,000 substorm onsets. These were identified through the SuperMAG collaboration and span three decades with continuous coverage. Solar cycle variations include a profound minima in 2009 (448 substorms) and peak in 2003 (3727). The magnitude of this variation (a factor of 8.3) is not explained through variations in estimators of the frontside merging rate (such as d Φ MP / dt ), even when the more detailed probability distribution functions are examined. Instead, v , or better, n 1/2 v 2 seems to be implicated in the dramatic difference between active and quiet years, even beyond the role of velocity in modulating merging. Moreover, we find that although most substorms are preceded by flux loading (78.5% are above the mean and 83.8% above median solar wind driving) a high solar wind v is almost as important (68.3% above mean, 74.8% above median). This and other evidence suggests either v or n 1/2 v 2 (but probably not p ) plays a strong secondary role in substorm onset. As for the seasonal and diurnal effects, the elliptical nature of the Earth's orbit, which is closest to the Sun in January, leads to a larger solar wind driving (measured by Bs , vBs , or d Φ MP / dt ) in November, as is confirmed by 22 years of solar wind observations. However substorms peak in October and March, and have a UT dependence best explained by whether a conducting path established by solar illumination exists in at least one hemisphere in the region where substorm onsets typically occur.

Description: [1]  The primary sources of energetic electron precipitation (EEP) which affect altitudes 〈100 km (〉30 keV) are expected to be from the radiation belts, and during substorms. EEP from the radiation belts should be restricted to locations between L  = 1.5-8, while substorm produced EEP is expected to range from L  = 4-9.5 during quiet geomagnetic conditions. Therefore, one would not expect any significant D-region impact due to electron precipitation at geomagnetic latitudes beyond about L  = 10. In this study we report on large unexpectedly high latitude D-region ionization enhancements, detected by an incoherent scatter radar at L  ≈ 16, which appear to be caused by electron precipitation from substorms. We go on to reexamine the latitudinal limits of substorm produced EEP using data from multiple low-Earth orbiting spacecraft, and demonstrate that the precipitation stretches many hundreds of kilometers polewards of the previously suggested limits. We find that a typical substorm will produce significant EEP over the IGRF L -shell range L  = 4.6 ± 0.2-14.5 ± 1.2, peaking at L  = 6-7. However, there is significant variability from event to event; in contrast to the median case, the strongest 25% of substorms have significant EEP in the range spaning L  = 4.1 ± 0.1-20.7 ± 2.2, while the weakest 25% of substorms have significant EEP in the range spaning L  = 5.5 ± 0.1-10.1 ± 0.7. We also examine the occurrence probability of very large substorms, focusing on those events which appear to be able to disable geostationary satellites when they are located near midnight MLT. On average these large substorms occur approximately 1-6 times per year, a significant rate given the potential impact on satellites.

Description: [1]  This paper presents new observations of the behaviour of simulated dust particles in space plasma based on a 3D particle in cell code. Multistep Monte Carlo collision is employed to simulate the dust charging process which is validated for the cases of charging of isolated dust particle and ensemble dust particles, where results indicate good agreement between simulation and theories. The code is then used to investigate plasma properties near a charged surface in a vicinity of a cloud of dust particles. The simulation reveals that a cloud of dust particle close to a spacecraft surface affects plasma densities around the spacecraft as well the spacecraft's surface potential. It is suggested that dust cloud causes the surface to charge to higher negative potential. The simulation also suggests that the combination of surface potential and dust cloud potential produces a region of trapped low energy electrons.

Description: [1]  We here document with magnetic field observations a passage of the MESSENGER spacecraft through Mercury's magnetosphere under conditions of a quasi-parallel bow shock, i.e., when the direction of the upstream interplanetary magnetic field (IMF) was within 45° of the bow shock normal. The spacecraft's fast transition of the magnetosheath and the steady solar wind conditions during the period analyzed allow both spatial and temporal properties of the shock crossing to be investigated. The observations show that the shock reformation process can be nearly periodic under stable solar wind conditions. Throughout the 25-min-long observation period, the pulsation duration deviated by at most ~10% from the average 10 s period measured. This quasi-periodicity allows us to study all aspects of the shock reconfiguration, including ultra-low-frequency waves in the upstream region and large-amplitude magnetic structures observed in the vicinity of the magnetosheath − solar wind transition region and inside the magnetosheath. We also show that bow shock reformation can be a substantial source of wave activity in the magnetosphere, on this occasion having given rise to oscillations in the magnetic field with peak-to-peak amplitudes of 40–50 nT over large parts of the dayside magnetosphere. The clean and cyclic behavior observed throughout the magnetosphere, the magnetosheath, and the upstream region indicates that the subsolar region was primarily influenced by a cyclic reformation of the shock front, rather than by a spatial and temporal patchwork of short large-amplitude magnetic structures (SLAMS), as is generally the case at the terrestrial bow shock under quasi-parallel conditions.

Description: [1]  The entry of solar wind into the magnetosphere is strongly influenced by kinetic-scale boundary layers where the rapid variation in the magnetic field and/or velocity can drive transport. In current layers with strong Alfvénic velocity shear, the generation of vortices from the Kelvin-Helmholtz instability can drive magnetic reconnection even in broader current sheets by locally compressing these layers as the vortices develop. Previous two-dimensional (2D) fully kinetic simulations of this vortex-induced reconnection process have demonstrated the copious formation of magnetic islands in regions of strongly compressed current between the vortices. Here we describe the first three-dimensional (3D) fully kinetic simulations of this process and demonstrate that the compressed current sheets give rise to magnetic flux ropes over a range of oblique angles and along the entire extent of the compressed current layer around the periphery of the vortex. These flux ropes propagate with the shear flow and eventually merge with the vortex. Over longer time scales, this basic scenario is repeated as the vortices drive new compressed current sheets. In the final stage, the vortices undergo a merging process that drives new compressed current sheets and flux ropes. Based on these simulations, a simple model is proposed that predicts the size of these flux ropes relative to their parent vortex. Both the relative sizes as well as the structure of the profiles across the vortex are in reasonable agreement with THEMIS observations at the Earth's low-latitude magnetopause.

Description: The intermetallic compounds Sr 2 Au 6.52 Zn 2.48 , Sr 2 Au 6 Zn 3 , and Sr 2 Au 6 Ga 3 were obtained by induction melting of the elements in sealed tantalum tubes. Their structures were studied by X-ray diffraction on powders and refined from single crystal diffraction data: R c , a = 844.5(2), c = 2187.7(5) pm, wR 2 = 0.0411, 936 F 2 values and 20 variables for Sr 2 Au 6.52 Zn 2.48 ; a = 841.6(2), c = 2191.5(7) pm, wR 2 = 0.0126, 587 F 2 values and 19 variables for Sr 2 Au 6 Zn 3 ; and a = 841.9(2), c = 2191.1(7) pm, wR 2 = 0.0199, 660 F 2 values and 19 variables for Sr 2 Au 6 Ga 3 . The gold substructures of Sr 2 Au 6 Zn 3 and Sr 2 Au 6 Ga 3 can be considered as diamond polytypes with 6R stacking sequences (287–304 pm Au–Au in Sr 2 Au 6 Zn 3 ). The cavities formed by this network are filled in an ordered manner by strontium atoms and Zn 3 (281 pm Zn–Zn), respectively Ga 3 (286 pm Ga–Ga) triangles in a 2:1 ratio. Consequently one can describe the Sr 2 Au 6 Zn 3 and Sr 2 Au 6 Ga 3 structures as ordered substitution variants of the Zintl phase CaIn 2 . This structural relationship is discussed on the basis of a group-subgroup Scheme. Sr 2 Au 6.52 Zn 2.48 shows Zn/Au mixing on the triangle.

Description: The templated borate, [C 9 H 14 N] · [B 5 O 6 (OH) 4 ], was synthesized under hydrothermal conditions. Single crystal X-ray diffraction techonology reveals that it crystallizes in the triclinic system, space group P (No. 2). The material was also characterized by element analysis, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), thermogravimetric and differential thermal analysis (TG-DTA), and luminescence spectroscopy. The compound consisted of isolated pentaborate [B 5 O 6 (OH) 4 ] – and N -butylpyridinium cations [C 9 H 14 N] + . The [B 5 O 6 (OH) 4 ] – anions are connected together by hydrogen bonds to form a three-dimensional framework, in which [C 9 H 14 N] + cations are located in. [C 9 H 14 N] · [B 5 O 6 (OH) 4 ] exhibits tunable luminescence emission at 415–458 nm by means of heating treatment from 100 to 300 °C.

Description: Two alkylimido derivatives of hexamolybdate, (Bu 4 N) 2 [Mo 6 O 18 (≡N- o -COOCH 3 C 6 H 4 )] ( 1 ) and (Bu 4 N) 2 [Mo 6 O 18 (≡N- o -COOCH 2 CH 3 C 6 H 4 )] ( 2 ), were synthesized in high purity and good yields by the reaction of [(C 4 H 9 ) 4 N] 4 [α-Mo 8 O 26 ] and methyl anthranilate or ethyl- o -aminobenzoate hydrochloride with N , N ′-dicyclohexylcarbodiimide (DCC) as a dehydrating agent in dry acetonitrile solution, which were characterized by elemental analyses, IR, UV/Vis, and 1 H NMR spectroscopy as well as ESI-MS, and single-crystal X-ray diffraction study. Compound 1 crystallizes in the monoclinic space group P 2 1 / n with one-dimensional chain structure via intramolecular hydrogen bond. Compound 2 also crystallizes in the monoclinic space group P 2 1 / n with dimer structure by intramolecular hydrogen bonds and π–π interactions between the pairs of cluster anions.

Description: The cover picture shows the frontispieces of all articles published in this Special Issue with research reports from DFG priority program 1178 “Experimental Electron Density as Key to Understanding Chemical Interactions”, highlighting the diverse range of chemistry that is covered herein. Biological processes that determine the effects of drugs consist on a certain interaction between agent and receptor. This molecular recognition is influenced by the electron density distribution. Analysis of these processes enables the rational synthesis of drugs. Electron density measurements are moreover significant for the design of advanced materials with specific features, e.g. the development of new pigments. Thus, color, stability, and durability can be tuned by modifying the electron density. Selected substance classes used in chemical synthesis, drug design and material science were analyzed and their binding and recognition processes were studied and quantified by means of electron density measurements.

Description: [1]  We survey the properties of electron pitch angle distributions in the magnetotail plasma sheet at a distance between 15 and 19 R E from the Earth, using data from the Cluster PEACE instrument. We limit our survey to those pitch angle distributions measured when the IMF had been steadily northward or steadily southward for the previous three hours. We find that, at sub-keV energies the plasma sheet electron pitch angle distribution has an anisotropy such that there is a higher differential energyflux of electrons in the (anti-) field-aligned directions. Fitting the measured pitch angle distributions with both a single and two component kappa distribution reveals that this anisotropy is the result of the presence of a second, cold, component of electrons that is observed more often than not, and occurs during both the northward and southward IMF intervals. We present evidence that suggests the cold electron component has an ionospheric, rather than magnetosheath, source and is linked tothe large scale field aligned current systems that couple the magnetosphere and ionosphere.

Description: [1]  Driver functions for the Earth's magnetosphere-ionosphere system are derived from physical principles. Two processes act simultaneously: a reconnection-coupled MHD generator G and a viscous interaction. G accounts for the dayside reconnection rate, the length of the reconnection X-line, and current-saturation limits for the solar-wind generator. Two viscous drivers are derived: Bohm viscosity B and the freestream-turbulence effect F. A problematic proxy effect is uncovered wherein the viscous driver functions also describe the strength of reconnection. Two magnetospheric-driver functions written in terms of upstream-solar-wind parameters are constructed: G+B and G+F. The driver functions are tested against 7 geomagnetic indices. The reaction of the geomagnetic indices to G+B and G+F is nonlinear: nonlinear versions of the driver functions are supplied. Applying the driver functions at multiple timesteps yields correlation coefficients of ~85% with the AE and Kp indices; it is argued that multiple timestepping removes high-frequency uncorrelated signal from the drivers. Autocorrelation-function analysis shows strong 1-d and 1-yr periodicities in the AE index that are not in the solar-wind driver functions; correspondingly, highpass and lowpass filtering finds uncorrelated signal at 1-d and 1-yr timescales. Residuals (unpredicted variance) between the geomagnetic indices and the driver functions are analyzed: the residuals are anti-correlated with the solar-wind velocity, the solar F 10.7 radio flux, and the solar-wind current-saturation parameter. Removing diurnal, semiannual, and annual trends from the indices improves their correlation with the solar-wind driver functions. Simplified versions of the driver functions are constructed: the simplified drivers perform approximately as well as the full drivers.

Description: [1]  Plasma properties of Saturn's pre-midnight tail region are surveyed using Cassini/CAPS ion observations from 2010. Only low-latitude (|lat| 〈 6°) intervals in which the CAPS viewing was roughly symmetric inward and outward around the corotation direction are used. Our numerical moments algorithm returns nonzero ion density for 70% (999) of the intervals selected. Of these, 642 had detectable water-group ion densities, and the remainder were dominantly, if not entirely, light ions. The derived plasma parameters are similar to those found in an earlier study for the post-midnight tail region, except that we find little evidence for the systematic outflows identified in that study, and we do find numerous significant inflow events. One such inflow is identified as a dipolarization event, the first reported plasma properties of such a structure at Saturn. A second, long-lasting event may be evidence for the existence at times of a quasi-steady reconnection region in the pre-midnight tail. The large majority of the plasma flows are found to be within 20° of the corotation direction, though with flow speeds significantly lower than full corotation. While the inflow events represent plausible evidence for internally-driven mass loss in the pre-midnight region, the absence of significant outflow events suggests that in the region surveyed here, tail reconnection has not yet proceeded to involve lobe field lines, so the disconnected plasma continues its general motion in the corotation direction.

Description: [1]  Following the first-time ionospheric imaging of a seismic fault, here we perform a case-study on retrieval of parameters of the extended seismic source ruptured during the great M9.0 Tohoku-oki earthquake. Using 1Hz ionospheric GPS data from the Japanese network of GPS receivers (GEONET) and several GPS satellites, we analyze spatio-temporal characteristics of co-seismic ionospheric perturbations and we obtain information on the dimensions and location of the sea surface uplift (seismic source). We further assess the criterion for the successful determination of seismic parameters from the ionosphere: the detection is possible when the line-of-sights from satellites to receivers cross the ionosphere above the seismic fault region. Besides, we demonstrate that the multi-segment structure of the seismic fault of the Tohoku-oki earthquake can be seen in high-rate ionospheric GPS-data. Overall, our results show that, under certain conditions, ionospheric GPS-derived TEC measurements could complement the currently working systems, or independent ionospherically-based system might be developed in the future.

Description: [1]  The non-dipolar portions of the Earth's main magnetic field constitute substantial differences between the two hemispheres. Beside the magnetic flux densities and patterns being different in the Northern Hemisphere (NH) and Southern Hemisphere (SH), also the offset between the invariant magnetic and the geographic poles is larger in the SH than in the NH. We investigated the effects of this magnetic field asymmetry on the high-latitude thermosphere and ionosphere using global numerical simulations, and compared our results with recent observations. While the effects on the high-latitude plasma convection are small, the consequences for the neutral wind circulation are substantial. The cross-polar neutral wind and ion drift velocities are generally larger in the NH than the SH, and the hemispheric difference shows a semidiurnal variation. The neutral wind vorticity is likewise larger in the NH than in the SH, with the difference probably becoming larger for higher solar activity. In contrast, the spatial variance of the neutral wind is considerably larger in the SH polar region, with the hemispheric difference showing a strong semidiurnal variation. Its phase is similar to the phase of the semidiurnal variation of the hemispheric magnitude differences. Hemispheric differences in ion drift and neutral wind magnitude are most likely caused partly by the larger magnetic flux densities in the near-polar regions of the SH, and partly by the larger offset between the invariant and geographic pole in the SH, while differences in spatial variance are probably just caused by the latter. We conclude that the asymmetry of the magnetic field, both in strength and in orientation, establishes substantial hemispheric differences in the neutral wind and plasma drift in the high-latitude upper atmosphere, which can help to explain observed hemispheric differences with EDI/Cluster and CHAMP.

Description: [1]  We have identified 8 events with double-belt structure in the outer radiation belt from 110 CME-driven magnetic storms and 223 CIR-driven storms during 1994 to 2003 based on the SAMPEX data sets. Among them, 3 cases are related to CME-driven magnetic storms and 5 cases are related CIR-driven storms. All double-belt structure events in the outer radiation belt are found during the recovery phase of a magnetic storm for both CME- and CIR-related events—they usually start to form within 3–4 days after the onset of the magnetic storm. The pre-conditions needed to form a double-belt structure, for all the CME-related events, are found to be high solar wind dynamic pressure ( P dy ) and southward IMF Bz; Nevertheless, for the CIR-related events, they are found to be associated with high speed stream with southward interplanetary magnetic field, which is enhanced by a suitably orientated B y component.It is further found that the flux distributions of the double-belt structure can be fitted well with a simply exponential decay function of L ∗ . Based on the RBC index, the proportion of the total number of 1.5-6.0 MeV electrons inside the position of maximum fluxes to that outside the maximum fluxes keeps rising during the double-belt period, which implies that the acceleration mainly occurs at regions inside the location of maximum fluxes. We suggest that the plasmapause and the strong wave-particle interactions with VLF and ULF waves near it, play an important role in the development of the double-belt structures.

Description: [1]  The solar minimum period during 2008–2009 was characterized by lower thermospheric density than the previous solar minimum, and lower than any previously measured. Recent work [ Solomon et al ., 2010; 2011] used the NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model to show that the primary cause of density changes from 1996 to 2008 was a small reduction in solar extreme-ultraviolet irradiance (EUV), causing a decrease in thermospheric temperature and hence a contracted thermosphere. There are similar effects in the ionosphere, with most measurements showing an F -region ionosphere that is unusually low in density, and in peak altitude. This paper addresses the question of whether model simulations previously conducted, and their solar, geomagnetic, and anthropogenic inputs, produce ionospheric changes commensurate with observations. We conducted a 15-year model run and obtained good agreement with observations of the global mean thermospheric density at 400 km throughout the solar cycle, with a reduction of ~30% from the 1996 solar minimum to 2008–2009. We then compared ionosonde measurements of the mid-day peak density of the ionospheric F -region ( N m F 2 ) to the model simulations at various locations. Reasonable agreement was obtained between measurements and the model, supporting the validity of the neutral density comparisons. The global average N m F 2 was estimated to have declined between the two solar minima by ~15%. In these simulations, a 10% reduction of solar EUV plays the largest role in causing the ionospheric change, with a minor contribution from lower geomagnetic activity, and a very small additional effect from anthropogenic increase in CO 2 .

Description: [1]  We report the statistical features of sporadic sodium layers (SSLs) and the thermospheric enhanced sodium layers (TeSLs) observed by a lidar chain located at Beijing (40.2°N, 116.2°E), Hefei (31.8°N, 117.3°E), Wuhan (30.5°N, 114.4°E), and Haikou (19.5°N, 109.1°E). The average SSL occurrence rate was approximately 46.0, 12.3, 13.8, and 15.0 hr per SSL at Beijing, Hefei, Wuhan, and Haikou, respectively. However, the TeSLs occurred relatively infrequently and were more likely to appear at low and high latitudinal sites. Both the SSLs and TeSLs at four lidar sites showed evident summer enhancements and correlated well with Es ( f o E s  〉  4  MHz ). The co-observations of SSLs at three lidar site pairs, i.e., Hefei – Beijing, Hefei – Wuhan and Hefei – Beijing, indicated that a large-scale SSL extended horizontally for at least a few hundred kilometers and exhibited a tidal-induced modulation. Moreover, the SSLs were better correlated for the Hefei – Wuhan and Hefei – Haikou pairs than the Hefei – Beijing pair, which suggested a difference in the dynamical/chemical process in mesosphere and lower thermosphere (MLT) between the Beijing site and the other sites.

Description: [1]  A highly sensitive all-sky EMCCD airglow imager has been operative in Longyearbyen, Norway (78.1°N, 15.5°E) since October 2011. The imager obtains the 630.0 nm all-sky images with an exposure time of 4 sec, which is about 10 times shorter than the conventional cooled CCD airglow imagers. This new equipment allows us to image the on-going structuring of polar cap patches in 2D fashion. Here, we report a case in which faint undulations appeared along the trailing edge of patches propagating in the central polar cap. The separation between the fingers in the undulations was about 50–100 km and the e -folding time of their growth was ~5 min. We suggest that the gradient-drift instability (GDI) is one of the possible generation mechanisms of the undulating structures. The reasons for this interpretation are 1) the asymmetry in the preference of structuring between the leading and trailing edges is qualitatively consistent with the GDI mechanism, and 2) the linear growth rate of GDI calculated by using electron density estimates from simultaneous EISCAT Svalbard radar observations is roughly consistent with the observed growth time of the fingers. Such “unstable polar cap patches" could be important sources of seed irregularities, which would eventually be broken down to smaller-scale density perturbations affecting the trans-ionospheric satellite communications in the central polar cap.

Description: . Reactions of the coordinatively unsaturated complexes [Fe 2 (μ-P R 2 )(μ-P R ′ 2 )(CO) 5 ] [ R = R ′ = t Bu ( 1 ); R = t Bu, R ′ = Cy ( 2 )] with nitric oxide in toluene at elevated temperatures were investigated. Thus, the new complexes [Fe 2 (μ-P t Bu 2 ) 2 (NO) 4 ] ( 3 ) and [Fe 2 (μ-P t Bu 2 )(μ-PCy 2 )(NO) 4 ] ( 4 ) were obtained in good yields. The molecular structure of 3 was confirmed by X-ray diffraction study. Compound 4 was also prepared from the coordinatively saturated species [Fe 2 (μ-P t Bu 2 )(μ-PCy 2 )(CO) 6 ] ( 2a ) with nitric oxide in refluxing toluene. Further closely related reactions at 60 °C with the complex 1 and [FeRu(μ-P t Bu 2 ) 2 (CO) 5 ] ( 5 ), respectively, were investigated using preliminary crystal structure determination results.

Description: [1]  As the Polar spacecraft apogee precessed through the magnetic equator in 2001, Polar encountered numerous substorm events in the region between geosynchronous orbit and 10 Re geocentric distance; most of them in the plasma sheet boundary layers. Of these, a small number were recorded near the neutral sheet in the evening sector. Polar/TIDE provides a unique perspective on the lowest energy ion plasma, showing that these events exhibited a damped wavelike character, initiated by a burst of radially outward flow transverse to the local magnetic field at ~ 80 km/sec. They then exhibit strongly damped cycles of inward/outward flow with a period of several minutes. After one or two cycles, they culminated in a hot plasma electron and ion injection, quite similar to those observed at geosynchronous orbit. Cold plasmaspheric plasmas comprise the outward flow cycles, while the inward flow cycles contain counter-streaming field-parallel polar wind like flows. The observed wave-like structure, preceding the arrival of an Earthward moving substorm injection front, suggests an outward displacement driven by the inward motion at local times closer to midnight, that is, a “snowplow” effect. The damped in/out flows are consistent with interchange oscillations driven by the arrival at the observed local time by an injection originating at greater radius and local time.

Description: Two new materials of the composition ({CH 3 (CH 2 ) 15 (CH 3 ) 2 S} + ) 2 [CoBr 4 ] 2– ( 1 ) and ({CH 3 (CH 2 ) 15 (CH 3 ) 2 S} + ) 2 [CuBr 4 ] 2– ( 2 and 3 ), of which the latter exists in two polymorphs, were synthesized. The materials display the synthetically targeted structures, comprising of layers of complex metal ions and layers of long-chain sulfonium cations. The crystal structures of the materials were determined. The interlayer distances are around 24 Å, with metal–metal distances about 8 Å. The magnetic properties of 1 were investigated, and the material is paramagnetic. ({CH 3 (CH 2 ) 15 (CH 3 ) 2 S} + ) 2 [CuBr 4 ] 2 is polymorphic. Both polymorphs crystallize with triclinic symmetry.

Description: [1]  Accurate knowledge of the global distribution of magnetospheric chorus waves is essential for radiation belt modeling because it provides a direct link to understanding radiation belt losses and acceleration processes. In this paper, we report on newly developed models of the global distribution of chorus amplitudes based on in-situ measurements of IMF and solar wind parameters as well as geomagnetic indices using an artificial neural network technique. We find that solar wind speed and IMF B Z are the most influential parameters that affect the evolution of the magnetospheric chorus. The variations of chorus amplitudes in the outer ( L  ≥ 7) and in the inner (5 ≤  L  〈 7) regions, respectively, are well correlated with the variations of solar wind speed and IMF B Z . In addition, the solar wind parameter-based chorus model generally results in a slightly higher correlation between measured and modeled chorus amplitudes than any other models including geomagnetic indices AE, Kp, and Dst. The developed model shows that the chorus is amplified near the pre-noon sector during the geomagnetically disturbed conditions. With increasing southward IMF B Z the location of peak chorus amplitude moves from the pre-noon sector to the midnight sector, which is due to the enhanced electron injection near midnight. We also present a comparison of diffusive transport simulations for radiation belt electrons interacting with two newly developed chorus models, solar wind parameter-based and geomagnetic index-based chorus models. The comparison between two models shows that the modeling outside the plasmapause can affect the dynamic even inside the plasmasphere because the populations outside the plasmapause can act as seed population to radiation belt particles inside the plasmapause. One weakness of our chorus modeling is that it is trained during the early phase of solar cycle 24 where very few strong storms occurred. Therefore, our model might not be valid in reproducing the chorus activity under extremely disturbed conditions, which should be updated in the future once chorus measurements for such conditions become available.

Description: [1]  We investigate the storm-scale morphology of the magnetospheric magnetic field as well as underlying distributions of electric currents, equatorial plasma pressure and entropy for four Steady Magnetospheric Convection (SMC) events that occurred during the May 2000 and October 2011 magnetic storms. The analysis is made using the empirical geomagnetic field model TS07D, in which the structure of equatorial currents is not predefined and it is dictated by data. The model also combines the strengths of statistical and event-oriented approaches in mining data for the reconstruction of the magnetic field. The formation of a near-Earth minimum of the equatorial magnetic field in the midnight sector is inferred from data without ad hoc assumptions of a special current system postulated in earlier empirical reconstructions. In addition, a new SMC class is discovered where the minimum equatorial field is substantially larger and located closer to Earth. The magnetic field tailward of the minimumis also much larger, and the corresponding area of accumulated magnetic flux may occupy a very short tail region. The equatorial current and plasma pressure are found to be strongly enhanced far beyond geosynchronous orbit and in a broad local time interval covering the whole nightside region. This picture is consistent with independent recent statistical studies of the SMC pressure distributions, global MHD and kinetic RCM-E simulations. Distributions of the flux tube volume and entropy inferred from data reveal different mechanisms of the magnetotail convection crisis resolution for two classes of SMC events.

Description: [1]  Drifts in the Parker spiral interplanetary magnetic field are known to be an important component in the propagation of galactic cosmic rays, while they are thought to be negligible for Solar Energetic Particles (SEPs). As a result they have so far been ignored in SEP propagation modelling and data analysis. We examine drift velocities in the Parker spiral within single particle first-order adiabatic theory, in a local coordinate system with an axis parallel to the magnetic field. We show that, in the presence of scattering in interplanetary space, protons at the high end of the SEP energy range experience significant gradient and curvature drift. In the scatter-free case, drift due to magnetic field curvature is present. The magnitude of drift velocity increases by more than an order of magnitude at high heliographic latitudes compared to near the ecliptic; it has a strong dependence on radial distance r from the Sun, reaching a maximum at r ~1 AU at low heliolatitudes and r ~10 AU at high heliolatitudes. Due to the mass over charge dependence of drift velocities, the effect of drift for partially ionised SEP heavy ions is stronger than for protons. Drift is therefore likely to be a considerable source of cross field transport for high energy SEPs.

Description: [1]  We present a novel method for the automatic retrieval of local plasma density measurements from the Mars advanced radar for sub-surface and ionospheric sounding (MARSIS) active ionospheric sounder (AIS) instrument. The resulting large data set is then used to study the configuration of the Martian ionosphere at altitudes above ~300 km. An empirical calibration routine is used, which relates the local plasma density to the measured intensity of multiple harmonics of the local plasma-frequency oscillation, excited in the plasma surrounding the antenna in response to the transmission of ionospheric sounding pulses. Enhanced accuracy is achieved in higher-density ( n e  〉 150 cm − 3 ) plasmas, when MARSIS AIS is able to directly measure the fundamental frequency of the local plasma oscillation. To demonstrate the usefulness of this data set, the derived plasma densities are binned by altitude and solar zenith angle (SZA) in regions over weak ( nT) and strong ( nT) crustal magnetic fields, and we find clear and consistent evidence for a significant asymmetry between these two regions. We show that within the ~300-1200 km altitude range sampled, the median plasma density is substantially higher on the dayside in regions of relatively stronger crustal fields than under equivalent illuminations in regions of relatively weaker crustal fields. Conversely, on the nightside, median plasma densities are found to be higher in regions of relatively weaker crustal fields. We suggest that the observed asymmetry arises as a result of the modulation of the efficiency of plasma transport processes by the irregular crustal fields, and the generally horizontal draped interplanetary magnetic field (IMF).

Description: [1]  Global models of the Van Allen radiation belts usually include resonant wave-particle interactions as a diffusion process, but there is a large uncertainty over the diffusion rates. Here we present a new diffusion matrix for whistler mode chorus waves that can be used in such models. Data from seven satellites are used to construct 3,536 power spectra for upper and lower band chorus for 1.5 ≤  L ∗  ≤ 10, MLT, magnetic latitude 0 o  ≤ | λ m | ≤ 60 o and five levels of K p . Five density models are also constructed from the data. Gaussian functions are fitted to the spectra and capture typically 90% of the wave power. The frequency maxima of the power spectra vary with L ∗ and are typically lower than that used previously. Lower band chorus diffusion increases with geomagnetic activity and is largest between 21:00 and 09:00 MLT. Energy diffusion extends to a few MeV at large pitch angles 〉 60 o and at high energies exceeds pitch angle diffusion at the loss cone. Most electron diffusion occurs close to the geomagnetic equator (〈 12 o ). Pitch angle diffusion rates for lower band chorus increase with L ∗ and are significant at L ∗  = 8 even for low levels of geomagnetic activitywhile upper band chorus is restricted to mainly L ∗  〈 6. The combined drift and bounce averaged diffusion rates for upper and lower band chorus extend from a few keV near the loss cone up to several MeV at large pitch angles indicating loss at low energies and net acceleration at high energies.

Description: [1]  We report that radio science (RS) experiment onboard Mars Express (MEX) have observed three plasma layers in the nighttime ionosphere of Mars at altitudes ~80-100 km, ~120 km and ~160 km, which are reproduced by model calculation due to impact of meteoroid, solar wind proton and electron respectively. The densities of 21 ions (Mg + , Fe + , Si + , MgO + , MgCO 2 + , MgO 2 + , MgN 2 + , FeO + , FeO 2 + , FeN 2 + , FeCO 2 + , SiO + , SiCO 2 + , SiN 2 + , SiO 2 + , CO 2 + , N 2 + , O + , O 2 + , CO + , and NO + ) have been computed between altitude 50 km and 200 km. The model shows that all atmospheric ions (CO 2 + , N 2 + , O + , CO + , O 2 + and NO + ) are produced above 100 km due to solar wind electron and proton impact ionizations. The metallic ions are formed between 50 km and 100 km due to ablation of micrometeoroids. It is found that mass ~3.0 × 10 -4  g of incoming meteoroid is sufficient for meteor ablation and its characteristic flux ~4.0 × 10 -15  cm -2  s -1 could produce the nighttime metallic layer observed by MEX. The calculated electron densities are also compared with the occultation measurements made by Mars 4/5 in the nighttime ionosphere of Mars.

Description: [1]  Ultra Low Frequency (ULF) waves transfer energy in the Earth's magnetosphere through a variety of mechanisms that impact the Earth's ionosphere, radiation belts, and other plasma populations. Measurements of the electromagnetic portion of the energy transfer rate are an important source of information for assessing the importance of ULF waves relative to other energy transfer mechanisms as well as a diagnostic for studying the behavior of ULF waves. Using THEMIS satellite data, we examine the time averaged electromagnetic energy transfer rate, or Poynting vector, as a function of frequency and region of the magnetosphere; for this study, we focus on the direction and rate of energy transfer relative to the background magnetic field, comparing perpendicular and parallel transfer rates. This study extends earlier studies of the ULF wave Poynting vector that focused on narrower frequency ranges or specific regions of the magnetosphere; here, we consider the 3–50 mHz frequency range, all local time sectors, radial distances from 3 to 13 Re, and magnetic latitudes close to the equatorial plane. We measure time averaged Poynting vectors that range from  10 − 11 to 10 − 5 W / m 2 , with larger Poynting vector magnitudes occurring at largerradial distances and smaller frequencies. In every spatial region and frequency we examined, we found a large degree of scatter in both the Poynting vector magnitude and direction. The Poynting vector tends to be anisotropic at all frequencies,with more energy transferred along rather than across the background magnetic field. This preference for parallel energy transfer near the magnetic equator suggests that Joule dissipation in the ionosphere and the acceleration of auroral electrons are the largest sinks of ULF wave energy in the magnetosphere.

Description: [1]  Previous statistical studies have found a close relationship between high speed streams and high latitude geomagnetic activity. The speed by itself would increase the geoeffectivity of the solar wind. But it is also believed that pure Alfvénic fluctuations, often found in the trailing part of the streams, play a role in the solar wind driving of geomagnetic activity by amplifying the north-south component of the magnetic field ( B Z ), and thereby the dayside reconnection electric field. By automatically identifying slow and fast solar wind streams and by analysing them for more than one solar cycle, we aimed to study the relation between speed, Alfvénicity and B Z in the solar wind. It was found out that streams whose trailing parts are dominated by pure Alfvénic fluctuations, are the most geoeffective streams, on average. However, it is not the pure Alfvénic fluctuations themselves which cause the streams to be more geoeffective. There is only a variation of about 10 % in B Z due to the Alfvénicity of the fluctuations. Instead the streams are more geoeffective because the pure Alfvénic fluctuations tend to occur during high solar wind speed and strong IMF. There is a substantial variation within the solar cycle of how Alfvénic the solar wind streams are, and years with many extremely Alfvénic streams tends to have more days with moderately large geoeffectivity. The list of solar wind streams is included as extra material to this paper.

Description: [1]  Data Interpolating Empirical Orthogonal Functions (DINEOFs) are a data-based method for determining a few orthogonal basis functions that optimally reproduce a given data set. This technique is applied to meridional drift measurements performed by the Coupled Ion Neutral Dynamics Investigation (CINDI) onboard the Communication/Navigation Outage Forecasting System (C/NOFS) as well as electron density profiles derived from GPS Radio Occulations (RO) performed by COSMIC. The low densities of the equatorial ionosphere spanning 2009 - 2010 restricted quality drift measurements by CINDI to altitudes near perigee, limiting the local time coverage of measurements. Full local time descriptions may be obtained as perigee moves through all local times though this requires a minimum 67 day season. To increase the data coverage of the ionosphere CINDI data is supplemented with COSMIC GPS RO data. DINEOFs are applied to median meridional drift measurements as well as COSMIC measurements spanning 2009-10 and are used to make a best estimate of the equatorial ionosphere at locations not observed. The scattered distribution of COSMIC profiles as well as the physical relationship between meridional ion drifts and the distribution of density with altitude improve thequality of the reconstructions compared to using CINDI alone. The DINEOF reconstructions demonstrate that the annual anomomly of reduced ionospheric densities in June compared to December measured by COSMIC is coincident with a change in the meridional ion drifts at the geomagnetic equator measured by CINDI.

Description: Single crystals of Rb 2 H 2 P 2 O 6 · 2H 2 O could be obtained from aqueous solutions of hypodiphosphoric acid and rubidium carbonate. Its crystal structure was determined by X-ray diffraction and it crystallizes in the monoclinic space group P 2 1 / c with Z = 4. The salt-like title compound consists of [H 2 P 2 O 6 ] 2– units in staggered P 2 O 6 -skeleton conformation, Rb + cations, and H 2 O molecules, held together by intermolecular hydrogen bonds of the type O ··· O. The vibrational spectra (IR/FIR and Raman) of the rubidium salt were recorded and an assignment of the vibrational modes is proposed based on the point group C 2 h for the P 2 O 6 -skeleton of the anion. The thermal behavior of Rb 2 H 2 P 2 O 6 · 2H 2 O is dominated by a complex TG decay indicating a simultaneous H 2 O delivery coupled with a disproportionation of [H 2 P 2 O 6 ] 2– , what is also supported by Raman spectra of heated samples.

Description: Three metal coordination polymers {[Co(L) 2 (H 2 O) 2 ] 2+ · 2NO 3 – } n ( 1 ), {[Mn(L) 2 (H 2 O) 2 ] 2+ · 2Cl – · 3H 2 O} n ( 2 ), and [ZnL(ba) 2 ] n ( 3 ) [L = 3, 5-bis(imidazole-1-yl)pyridine and Hba = benzoic acid] were synthesized and structurally characterized by IR spectroscopy, elemental analysis, X-ray powder diffraction, and X-ray single crystal diffraction. Complex 1 shows a one-dimensional (1D) chain structure. Adjacent chains are connected by hydrogen bonding and nitrate groups to form a 3D network. Complex 2 features a 2D layer structure. A three-dimensional network is constructed through the cluster consisting of two chloride ions and three water molecules. Complex 3 shows a 1D zigzag chain structure that further twists together to form a 3D network. The X-ray powder diffraction patterns were compared with the simulated ones. Moreover, the luminescent properties of 1 – 3 were investigated in the solid state at room temperature, and the thermogravimetric analyses were carried out to study the thermal stability of the three complexes.

Description: . The reactions of FeCl 3 · 6H 2 O and 2-(2′-hydroxyphenyl)-2-thiazoline as a bidentate O-N donor thiazoline ligand (thoz) afford a five-coordinate Fe III complex [Fe(thoz) 2 Cl] with a distorted square pyramidal configuration. Complex [Fe(thoz) 2 Cl] was isolated as air-stable crystalline solids and fully characterized, including by single-crystal X-ray structure analysis. Complex [Fe(thoz) 2 Cl] shows very efficient reactivity in the oxidation of sulfides to their corresponding sulfoxides using urea hydrogen peroxide (UHP) as the oxidant at room temperature in air.

Description: Two copper(I) complexes of compositions [Cu(HL)I] 2 · EtOH ( 1 ) and [Cu(HL) 3 ]I · MeOH ( 2 ) were synthesized via the reactions of HL [HL = 2(4, 5-diphenyl-1 H -imidazol-2-yl)pyridine] and CuI in EtOH and MeOH, respectively, under solvothermal conditions. The complexes were characterized by X-ray single crystal diffraction, IR spectroscopy, and elemental analysis. Compounds 1 and 2 are catalytically active towards ketalization reaction, giving various ketals under mild conditions.

Description: Mineral samples from the Prasolovskoe epithermal Au-Ag deposit, Russia, were investigated via transmission electron microscopy (TEM). One component was identified as the mineral kurilite Ag 8 Te 3 Se according to the data obtained from electron diffraction (ED) and Fourier transform analyses of high resolution micrographs. Micrometer-sized grains of kurilite were found next to other noble metal chalcogenide domains like the hessite-type. The EDX microprobe analyses of the kurilite domains were determined with the chemical composition Ag 7.9 Au 0.1 Te 2.9 Se 1.0 which is consistent with kurilite doped by gold. Additionally noble metal polychalcogenidehalides (NMPH) were identified via ED. Monoclinic and tetragonal polymorphs of Ag 5 Te 2 Cl were observed for the first time in a mineral sample. One additional component, whose composition equates the kurilite-type component with regard to Ag, Au, Te, and Se but with a marginal chlorine component, crystallizes in a structure type known from synthetic NMPH, namely Ag 23 Te 12 X (X = Cl, Br). This phase as well as the phases Ag 10 Te 4 Br 3 and Ag 20 Te 10 Br 2 was found next to each other in an also investigated synthetic sample.

Description: [1]  It is well accepted that the propagation of electromagnetic ion cyclotron (EMIC) waves are bidirectional near their source regions and unidirectional when away from these regions. The generally believed source region for EMIC waves is around the magnetic equatorial plane. Here we describe a series of EMIC waves in the Pc1 (0.2-5 Hz) frequency band above the local He + cyclotron frequency observed in situ by all four Cluster spacecraft on 9 April 2005 at mid-magnetic latitudes (MLAT = ~33°-49°) with L = 10.7-11.5 on the dayside (MLT = 10.3-10.4). A Poynting vector spectrum shows that the wave packets consist of multiple groups of packets propagating bidirectionally, rather than unidirectionally, away from the equator, while the local plasma conditions indicate that the spacecraft are entering into a region sufficient for local wave excitation. One possible interpretation is that, while part of the observed waves are inside their source region, the others are either close enough to the source region, or mixed with the wave packets from multiple source regions at different latitudes.

Description: [1]  Using mesospheric temperature information obtained by Rayleigh lidar observations over Gadanki (13.5°N, 79.2°E) and temperature, chemical constituents and their exothermic chemical reaction heating rates obtained by Sounding of Atmosphere by Broadband Emission Radiometry (SABER) instrument onboard Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite over and near to Gadanki location, it is demonstrated that, the dominant role of chemical heating for the occurrence of a few large mesospheric inversion layer (MIL) events during January-February 2011. The heating rates due to exothermic chemical reactions among atomic oxygen (O), atomic hydrogen (H), molecular oxygen (O 2 ), ozone (O 3 ) and hydroxyl (OH) species are the key factors involved in the MIL formation. As relatively larger (lower) ozone mixing ratios are observed at the top (bottom) of the inversion layers, large heating rate (~ 15 K/day) is found to occur between 80 and 85 km due to the exothermic reaction between atomic hydrogen and ozone H + O 3  → OH + O 2 , which dominates all other important exothermic chemical reactions during these MIL events and the large volume emission rates of energy of O 2 , OH are found to be mostly due to the reaction between H and O 3. It is also demonstrated that dynamics plays a negligible role in the formation of these MILs as conditions for the convective and dynamic instability are found to be not satisfied during these MIL events.

Description: [1]  Bursty bulk flows (BBFs) play an important role for the mass, energy and magnetic flux transport in the plasma sheet, and the flow pattern in and around a BBF has important consequences for the localized energy conversion between the electromagnetic and plasma mechanical energy forms. The plasma flow signature in and around BBFs is often rather complicated. Return flows and plasma vortices are expected to exist at the flanks of the main flow channel, especially near the inner plasma sheet boundary, but also further down-tail. A dipolarization front (DF) is often observed at the leading edge of a BBF, and a flux pileup region (FPR) behind the DF. Here we present Cluster data of three FPRs associated with vortex flows observed in the mid-tail plasma sheet on August 15, 2001. According to the principles of Fu et al . [2011] and Fu et al . [2012c], two of the FPRs are considered to be in an early stage of evolution (growing FPRs). The third FPR is in a later stage of evolution (decaying FPR). For the first time, the detailed energy conversion properties during various stages of the FPR evolution have been measured. We show that the later stage FPR has a more complex vortex pattern than the two earlier stage FPRs. The two early stage FPR correspond to generators, E  ⋅  J  〈 0, while the later stage FPR only shows weak generator characteristics and is instead dominated by load signatures at the DF, E  ⋅  J  〉 0. Moreover, to our knowledge this is one of the first times BBF related plasma vortices have been observed to propagate over the spacecraft in the mid-tail plasma sheet at geocentric distances of about 18 R E . Our observations are compared to recent simulation results [ Wiltberger et al ., 2000; Birn et al ., 2011] and previous observations [ Fu et al ., 2011, 2012c; Pang et al ., 2012].

Description: Eight chelating resins were synthesized in high yields by supporting 2-aminomethylpyridine, 2, 2′-dipyridylamine, 1, 2-phenylenediamine and 1, 2-ethylenediamine on Merrifield and Wang resins, respectively. These resins were used both as support of reducing complexes and as alkali metal sensors. 16 stable and easy to prepare reducing complexes, derived from the chelating resins and LiBH 4 and NaBH 4 , were prepared in good yields. These complexes showed chemoselectivity to reduce aldehydes in a low molar ratio and short time reactions. The fluorescence-sensing behavior of the chelating resins for alkali metal was studied. The fluorescence response of the materials where 1, 2-phenylenediamine is supported on Merrifield and Wang resins indicate that they behave as sensors for Li + and K + , respectively.

Description: The reaction of Fe 3 (CO) 12 with (C 3 H 5 ) 2 NCS 2 K in THF at room temperature afforded a red-brown solution. Treatment of the thus-obtained solution with MeI and PhCH 2 Br afforded clusters 1 , (μ-MeS)Fe 2 (CO) 6 (μ 4 -S)Fe 2 (CO) 6 (μ-CN(C 3 H 5 ) 2 ), and 2 , (μ-PhCH 2 CO)Fe 2 (CO) 6 (μ 4 -S)Fe 2 (CO) 6 (μ-CN(C 3 H 5 ) 2 ). Their structures were unambiguously determined by X-ray crystallography. Therefore, this methodology provides a novel route for the syntheses of spiro-S Fe/S clusters with aminocarbyne ligands.

Description: This study presents the preparation of 5-azido-3-nitro-1 H -1,2,4-triazole ( 1 ) in both good yield and high purity, starting from commercially available chemicals in a three step synthesis. Furthermore, several metal and nitrogen-rich salts with sodium ( 3 ), potassium ( 4 ), cesium ( 5 ), silver ( 6 ), lead ( 7 ), ammonium ( 8 ), guanidinium ( 9 ), and aminoguanidinium ( 10 ) were prepared by simple acid-base reactions. All compounds were well characterized by various means, including vibrational (IR, Raman) and multinuclear ( 1 H, 13 C, 14 N, 15 N) NMR spectroscopy, mass spectrometry, and DSC. Additionally the structure of 7 was determined by single-crystal X-ray diffraction. The sensitivities towards various outer stimuli (impact, friction, electrostatic discharge) were determined according to BAM standards. The metal salts were tested as potential primary explosives utilizing various preliminary tests.

Description: With Sharpless' and Meldal's discovery of the immensely supportive effect that metal catalysis has on Huisgen's classical 1,3-dipolar cycloaddition, azides (RN 3 ) – long underappreciated in organic synthesis – suddenly got in the focus of attention as most crucial players in sensational ‘click chemistry'. Less noisy though with the same commitment and even a much broader scope of scientific topics and objectives, the inorganic azide chemistry has made just as great strides in the last few decades. This review (Part I) gives an introductory survey of the most important results, and informs about modern developments and general trends. Particular emphasis is placed on the recent successful approaches to highly unstable homoleptic azido metal complexes of the main group and early transition elements, as well as on the enormous structural versatility caused by the ‘flexidentate' N 3 – ligand with its unsurpassed bridging capacities. The presentation in this paper of selected compounds and reactions is meant, in a way, as a prelude to the [3+2]-cycloadditions of metal azides and related species which will be covered in-depths in Part II. A large part of the comments finally deals with applications in fields such as catalysis, high explosive performance or magnetism of metal compounds containing azide, today certainly one of the most attractive research areas world-wide.

Description: The long-chain ligand, 1-phenyl-3-methyl-4-heptanoyl-pyrazol-5-one (HL) and its zinc(II) complex ZnL 2 were synthesized. The structure and the properties of ZnL 2 were characterized by elemental analysis, IR spectroscopy, X-ray diffraction, and thermogravimetric analysis. The zinc ion is five-coordinated in a square-pyramidal environment by four oxygen atoms of the HL ligands in the equatorial plane and one water molecule in the axial position. The water molecule is directly bonded to Zn 2+ and involved in intermolecular hydrogen bonding network. The complex and its corresponding ligand were screened in vitro against some strains of the human pathogenic bacteria. The metal complex exhibits higher antibacterial activity than its corresponding ligand. The complex exhibits purple effect emission as the result of fluorescence from the intraligand emission excited state.

Description: The microporous metal-organic framework Cd 2 (ABTC)(H 2 O)(DMA) 2 · H 2 O · 3DMA ( 1 ) (H 4 ABTC = 3,3′,5,5′-azobenzenetetracarboxylic acid; DMA = N , N ′-dimethylacetamide) was prepared by solvothermal reaction and characterized. X-ray structure analysis revealed that compound 1 is a three-dimensional (3D) open framework with 2D channels. The topology is based on a PtS net, constructed of 4-connected rectangular ABTC 4– units with 4-connected tetrahedral dinuclear Cd 2 (CO 2 ) 4 (H 2 O)(DMA) 2 secondary building units (SBUs). The solid-state excitation-emission spectra showed that the strongest emission peak is at 403 nm upon excitation at λ = 287 nm.

Description: P(2-SHC 6 H 4 ) 3 ( PS 3 H 3 ) reacts with GaMe 3 (1:1) to give GaMe{P(2-SC 6 H 4 ) 2 (2-SHC 6 H 4 )-κ 3 S , S′,P } ( 1 ), which could be deprotonated with NEt 3 to give [NEt 3 H][GaMe{P(2-SC 6 H 4 ) 3 -κ 3 S , S′,P }] ( 2 ). The 1:2 reaction of E (2-SHC 6 H 4 ) 3 [ E = P ( PS 3 H 3 ), As ( AsS 3 H 3 )] with GaMe 3 gave the dinuclear complexes GaMe{ E (2-SC 6 H 4 ) 2 (2-S{GaMe 2 (THF)}C 6 H 4 )-κ 3 S , S′,E } [ E = P ( 3 ), As ( 4 )]. Serendipitous hydrolysis of 4 resulted in small amounts of the hexanuclear gallium hydroxide complex cyclo -{GaMe(μ-OH)} 6 {As(2-SC 6 H 4 ) 3 -κ S , S′,S′′ } 2 ( 5 ). Complexes 1 – 4 were fully characterized, complexes 2 – 5 also by X-ray crystallography.

Description: Topological aspects of the experimental electron density in TiB 2 reconstructed on base of the multipole model are obtained from high-resolution single-crystal X-ray diffraction data. The features of electron density are compared with quantum chemical calculations and analysed in terms of Quantum Theory of Atoms in Molecules for the interpretation of atomic interactions. In spite of some differences in the Laplacian, both experimental and calculated density confirmed two main bonding interactions. The B–B bond critical point suggests a shared-type interaction with pronounced ellipticity in the boron layer, whereas B–Ti bond critical point reveals an interaction intermediate between shared and closed-shell type. Both, theory and experiment indicate a non-structured spherical topology in the penultimate shell of Ti. Integration of the electron density over the atomic basins reveals a charge transfer of 1.1 e (experiment) and 1.4 e (theory) from titanium to boron network, respectively.

Description: [1]  We use the measurements by the Vector Electric Field Investigation (VEFI) on board the C/NOFS satellite to study the local time, seasonal, and longitudinal dependent climatology of equatorial F region zonal plasma drifts during 2008-2011. These drifts are essentially westward during the day and eastward at night. Over Jicamarca, the satellite measurements are in good agreement with incoherent scatter radar drifts. Our data show strong longitudinal variations, particularly in the South American sector during the solstices. The equinoctial data exhibit short-lived and largely enhanced westward drifts near sunrise, and wave-4 structures from theearly afternoon to late night equinoctial periods. The nighttime eastward drifts are largest near the western American sector at all seasons. The June solstice post-midnight eastward drifts decrease sharply at longitudes of about 310˚ and have much smaller values in the entire eastern hemisphere. We also briefly discuss the relationship between the longitude dependent vertical and zonal plasma drifts.

Description: The stannides Li 2 CuSn 2 and Li 2 AgSn 2 were synthesized by induction-melting (or in a muffle furnace) of the elements in sealed niobium ampoules. The new phases were characterized by powder X-ray diffraction. The structures of both stannides were investigated by X-ray diffraction on single crystals: Li 2 AuSn 2 type, I 4 1 / amd , a = 442.6(1), c = 1940.9(8) pm, wR 2 = 0.0742, 310 F 2 values for Li 2 CuSn 2 and a = 456.33(9) c = 2018.2(6) pm, wR 2 = 0.0626, 339 F 2 values for Li 2 AgSn 2 with 10 variables for each refinement. The transition metal ( T ) atoms have tetrahedral tin coordination. The T Sn 4 tetrahedra are condensed via common corners forming layers that are further condensed by Sn–Sn bonding, leading to three-dimensional [CuSn 2 ] and [AgSn 2 ] networks which leave distorted hexagonal channels for the lithium atoms. The lithium ions show considerable mobility, with activation energies of 0.29 and 0.47 eV extracted from variable temperature 7 Li solid state NMR spectra. 119 Sn Mössbauer spectra at 78 K show signals at isomer shifts of δ = 2.13(1) mm s –1 for Li 2 CuSn 2 and δ = 2.07(1) mm s –1 for Li 2 AgSn 2 . The signals show electric quadrupolar splitting because of the non spherical environment of the tin nuclei. A minor impurity of β-Sn could be identified in both spectra.

Description: The complexes [Ni 2 (L) 2 ] 2 · H 2 O ( 1 ) and [Cu 2 (L) 2 (H 2 O)] · 2CH 3 OH ( 2 ) were prepared by reaction of the chiral Schiff base ligand N -[(1 R ,2 S )-2-hydroxy-1, 2-diphenyl]-acetylacetonimine (H 2 L) with Ni II and Cu II ions, respectively, aiming to develop economically and environmentally-friendly catalysts for the hydrogenation of ketones. They have a dinuclear skeleton with axial vacant sites. The catalytic effects of the two complexes for hydrogenation of ketones were tested using dihydrogen gas as hydrogen source. They present some catalytic effects in hydrogenation of acetophenone, which has a dependence on the temperature and base used in these reactions. However, no apparent catalytic effects were found for the two complexes in hydrogenation of 4-nitroacetophenone and 4-methylacetophenone. Although the catalytic conversion in these hydrogenation reactions is low, they do represent a kind of cheap and environmentally-friendly hydrogenation catalyst.

Description: Poised to investigate the association of vanadium with physiological substrates in materials capable of exerting anticancer biological activity, pH-specific synthetic chemical reactivity between vanadium and triethyl ammonium acetate/trigonelline in aqueous and mixed organic-aqueous media led to the isolation of three new binary composite materials, namely K 2 [(MeN(+)C 5 H 4 COOH) 2 ][V 10 O 28 H 2 ] · 2H 2 O ( 1 ), [(H 2 N(+)Me 2 ) 4 ][V 10 O 28 H 2 ][Me 3 N(+)CH 2 COO(–)] 2 ( 2 ), and [(Me 3 N(+)CH 2 COOH) 4 ][V 10 O 28 H 2 ][Me 3 N(+)CH 2 COO(–)] 2 · 2H 2 O ( 3 ). 1–3 were characterized by elemental analysis, FT-IR and UV/Vis spectroscopy, Cyclic voltammetry, TGA-DTG, and X-ray crystallography. In all three compounds, the [V 10 O 28 H 2 ] 4– core unit is a common cluster assembly, with the vanadium in the +5 oxidation state. The counteracting cationic assembly in each composite material originates in the betaine starting reagent or the solvent out of which the materials crystallized. Biological activity studies of 1 and 3 in vitro in MCF-7 breast epithelial and A549 lung adenocarcinoma cell cultures show that both materials inhibit the viability of both cell lines in a dose-dependent fashion, in juxtaposition to the behavior of the betaine components present in these materials. Collectively, the herein studies a) reveal the uniquely defined synthetic methodologies and physicochemical properties of the variably assembled [V 10 O 28 H 2 ] 4– core units crystallized into the composite binary polyoxovanadate-betaine lattice structures, b) unravel the distinct cytotoxicity profile of the composite materials toward MCF-7 and A549 cells, and c) attest to their future potential as metallodrugs of pharmacological significance in anticancer activity.

Description: [1]  Long-term variation in the geomagnetic Sq field and the cause of the variation were examined. 　The amplitude of the geomagnetic Y component (Sq(Y)) in equinox was averaged for each year, and adopted as a proxy of the Sq field. Sq(Y) was combined with the ionospheric conductivity estimated by the IRI model to determine the dynamo electric field and neutral wind velocity by using the geomagnetic main field strength. It was found that the solar activity dependence of the Sq field could be almost completely attributed to the conductivity variation, and neutral winds tend to decrease when the solar activity increases Although the long-term variation in the dynamo field differed among observatories, these differences were mostly attributed to the locality of the geomagnetic secular variation, whereas the variations in neutral wind amplitude were nearly the same in all regions. On the other hand, no clear long-term variation in neutral wind was detected other than that by solar activity.

Description: The crystal structures of the alkali aluminium thiohypodiphosphates M I AlP 2 S 6 (M I = Li, Na) are reported. NaAlP 2 S 6 crystallizes in the orthorhombic space group Fdd 2 (no. 43) with a = 8.0400(2), b = 10.9452(2), c = 20.8801(4) Å, and V = 1837.44(7) Å 3 ( Z = 8). It is isostructural with AgAlP 2 S 6 , which is consistent with the similar ionic radii of Na and Ag. In contrast, LiAlP 2 S 6 crystallizes in a different structure type which has not been observed in the large number of thiohypodiphosphates reported so far. It crystallizes in the monoclinic space group C 2/ c (no. 15) with a = 6.783(3), b = 10.365(4), c = 11.776(4) Å, β = 94.399(5)°, and V = 825.46(5) Å 3 ( Z = 4).

Description: We present the synthesis of 7-(diphenylphosphine)-indole 1 ( HPinol ) as a novel mono- and bidentate P - and N, P -ligand and its coordination chemical behaviour towards the d 6 - and d 8 -transition metals rhodium(III), palladium(II) and rhenium(I). The reaction of 1 with [Cp*RhCl 2 ] 2 in a 1:2 molar ratio leads to the formation of the P -coordinated complex [RhCl 2 ( P –( HPinol ))] ( 2 ). In the presence of the weak base NEt 3 , HCl elimination occurs by forming the neutral amido-phosphine chelated complex [RhCl( N, P –( Pinol ))] ( 3 ). The same P - and N, P -coordination is observed for palladium(II), where two ligands 1 coordinate to the metal centre forming the neutral complexes [PdCl 2 ( P – HPinol ) 2 ] ( 4 ) and [Pd( N, P – Pinol ) 2 ] ( 5 ). The reaction of Re(CO) 5 Br in the presence of NEt 3 and PPh 3 delivers the amido-phosphine complex [Re(CO) 3 PPh 3 ( N, P – Pinol )] ( 6 ). All products were characterised by multinuclear NMR spectroscopy, MS and IR spectra as well as elemental analysis. Furthermore, crystal structures of ligand 1 and all complexes 2–6 are presented.

Description: [1]  We analyze data recorded from October 2010 to September 2011, during the ascending phase of the 24 th solar cycle, from an AIS-INGV (Advanced Ionospheric Sounder - Istituto Nazionale di Geofisica e Vulcanologia) ionosonde and a GISTM (GPS Ionospheric Scintillation and TEC Monitor) scintillation receiver, co-located at low-latitude in the Southern American longitudinal sector (Tucumán, 26.9°S, 294.6°E, mag. Lat. 15.5°S, Argentina). The site offers the opportunity to perform spread-F and GPS scintillation statistics of occurrence under the southern crest of the equatorial ionospheric anomaly. Spread-F signatures, classified into four types (strong range spread-F (SSF), range spread-F (RSF), frequency spread-F (FSF) and mixed spread-F (MSF)), the phase and amplitude scintillation index ( σ Φ and S 4 , respectively), the total electron content ( TEC ) and the rate of TEC ( ROT ) parameter, marker of the TEC gradients, that can cause scintillations, are considered. The seasonal behavior results as follows: the occurrence of all four types of spread-F is higher in summer and lower in winter, while the occurrence of scintillations peaks at equinoxes in the post-sunset sector and shows a minimum in winter. The correspondence between SSF and scintillations seems to be systematic, and a possible correlation between S 4 and FSF peaks is envisaged at the terminator. The investigation focused also on two particular periods, from 12 to 16 March 2011, and from 23 to 29 September 2011, both characterized by the simultaneous presence of SSF signatures and scintillation phenomena allowing to discuss the role of Travelling Ionospheric Disturbances as a strong candidate causing ionospheric irregularities.

Description: ABSTRACT [1]  Neutrons contribute a significant radiation dose at commercial passenger airplane altitudes. With cosmic ray energies 〉 1  GeV , these effects could in principle be propagated to ground level. Under current conditions, the cosmic ray spectrum incident on the Earth is dominated by particles with energies 〈 1  GeV . Astrophysical shocks from events such as supernovae accelerate high energy cosmic rays (HECRs) well above this range. The Earth is likely episodically exposed to a greatly increased HECR flux from such events. Solar events of smaller energies are much more common and short lived, but still remain a topic of interest due to the ground level enhancements (GLEs) they produce. The air showers produced by cosmic rays (CRs) ionize the atmosphere and produce harmful secondary particles such as muons and neutrons. Although the secondary spectra from current day terrestrial cosmic ray flux are well known, this is not true for spectra produced by many astrophysical events. This work shows the results of Monte Carlo simulations quantifying the neutron flux due to CRs at various primary energies and altitudes. We provide here lookup tables (described later) that can be used to determine neutron fluxes from proton primaries with total energies 1  MeV – 1 PeV . By convolution, one can compute the neutron flux for any arbitrary CR spectrum. This contrasts with all other similar work, which is spectrum dependent. Our results demonstrate the difficulty in deducing the nature of primaries from the spectrum of ground level neutron enhancements.

Description: [1]  Rayleigh lidar temperature observations over Gadanki show a few mesospheric inversion layer (MIL) events during 20-25 January 2007. The zonal mean removed SABER temperature shows warm anomalies around 50°E and 275°E indicating the presence of planetary wave of zonal wavenumber 2. The MIL amplitudes in SABER temperature averaged for 10°N-15°N and 70°E-90°E show a clear 2-day wave modulation during 20-28 January 2007. Prior to 20 January 2007, a strong 2-day wave (zonal wavenumber 2) is observed in the height region of 80-90 km and it gets largely suppressed during 20-26 January 2007 as the condition for vertical propagation is not favourable, though it prevails at lower heights. The 10-day mean zonal wind over Tiruneveli shows deceleration of eastward winds indicating the westward drag due to wave dissipation. The nightly mean MF radar observed zonal winds show the presence of alternating eastward and westward winds during the period of 20-26 January 2007. The two dimensional spectrum of Rayleigh lidar temperature observations available for the nights of 20, 22 and 24 January 2007 shows the presence of gravity wave activity with periods 18 min, 38 min, 38 min, and vertical wavelengths 6.4 km, 4.0 km, 6.4 km respectively. From the dispersion relation of gravity waves, it is inferred that, these waves are internal gravity waves rather than inertia gravity waves with the horizontal phase speeds of ~40 m/s, ~37 m/s and ~50 m/s respectively. Assuming the gravity waves are eastward propagating waves, they get absorbed only in the eastward local wind fields of the planetary wave thereby causing turbulence and eddy diffusion which can be inferred from the estimation of large drag force due to the breaking of gravity wave leading to the formation of large amplitude inversion events in alternate nights. The present study shows that, the mesospheric temperature inversion is caused mainly due to the gravity wave breaking and the inversion amplitude may get modulated by the interaction between gravity waves and planetary waves. The eddy diffusion associated with gravity wave drag may also cause suppression in the planetary wave activity.

Description: [1]  To evaluate whether ground magnetic responses traditionally viewed as signatures of substorm onset may be related to post-onset auroral streamers rather than to substorm onset seen in aurora, we have analyzed ground magnetic and all-sky image responses for 14 substorm onsets selected solely on imager coverage. We find evidence supporting this possibility, the response being approximately coincident for mid-latitude positive bay and Pi2 pulsation enhancements and for abrupt auroral zone H decreases at stations near a streamer. These are all signatures of current wedge formation, indicating that substorm current wedge formation may be more of a response to plasma sheet flow channels associated with post-onset streamers than to the process leading to auroral onset, and that the current wedge may develop via a series of distinctly narrower wedge-like structures. We also find evidence that periods of streamers can occur more than once during a substorm expansion phase, and can give magnetic signatures of multiple onsets even if there are no additional auroral onsets. Furthermore, the peak auroral zone H decreases are seen in association with streamers and at times varying from just a few minutes to well over a half hour after substorm auroral onset if there is a prolonged period of streamers. This indicates peak substorm AE and AL values are likely related to features of post-onset streamers and their locations relative to observing stations, and are not a measure of the strength of the substorm auroral onset processes. We discuss possible additional implications on substorm expansion phase development.

Description: [1]  We statistically examine the occurrence rate of electromagnetic ion cyclotron (EMIC) waves observed by AMPTE/CCE. We use the 8-Hz magnetic field dataset that covers the whole CCE mission period of nearly 4.5 years from Augutst 1984 to Janauary 1989, which is more than three times the period studied by Anderson et al. [1992] (~452 days). The large data volume allows us to evaluate the storm phase dependence of the spatial occurence pattern of EMIC waves. The major results of this study are summarized as follows. (a) The occurrence rate is below 5% on the nightside at all L. On the dayside the rate is 〈5% in the inner magnetosphere (L 〈 6), while it is higher than 5% in the outer magnetosphere (L ≥ 6), up to 25%. The highest rate appears in the afternoon sector. (b) The overall occurrence rate is higher for H-band events than He-band events, except for the opposite feature seen in the inner magnetosphere on the early afternoon-to-post midnight side (L 〈 6, 14 h 〈 MLT 〈 22 h). (c) H-band events occur frequently in the outer magnetosphere (L ≥ 7) in the afternoon sector, regardless of geomagnetic activity. Under quiet conditions, H-band events also occur in the outer magnetosphere on the morning side (4 h ≤ MLT 〈 8 h). (d) He-band events frequently occur in the inner magnetosphere (L 〈 7) on the pre-noon to dusk side (10 h ≤ MLT 〈 19 h) under disturbed conditions (Dst ≤ −50 nT). (e) The storm-time He-band waves are generated more frequently during the main phase than the recovery phase, with the main-phase wave excitation seen toward the afternoon-side outer magnetosphere (L 〉 7). The results indicate two independent major processes that cause EMIC wave excitation in the Earth's magnetosphere: one externally triggers H-band waves on the dayside, and the other internally excites He-band waves on the dusk to afternoon side. We suggest that the former is due to solar wind compression which leads to perpendicular adiabatic ion heating and in turn an increase in temperature anisotropy, and that the latter is caused by injections of new, highly energetic ion population from the plasma sheet, with its velocity distributions becoming pancake-like on the dusk-to-afternoon side. The frequent occurrence seen on the afternoon side, at a wide L range, and during the main/development phase, strongly suggests the significant role of the sunward surge of the plasmasphere and plasma plumes in the injection-associated (i.e., storm-time) EMIC wave generation.

Description: [1]  We performed a statistical study of downward moving protons and alpha particles of ~ keV energy (assumed to be of solar wind origin), inside the Martian induced magnetosphere from July 2006 to July 2010. Ion and electron data are from the Analyzer of Space Plasma and Energetic Atoms (ASPERA-3) package onboard Mars Express. We investigated the solar wind ion entry into the ionosphere, excluding intervals of low altitude magnetosheath encounters. The study compares periods of quiet solar wind conditions and periods of solar wind pressure pulses, including interplanetary coronal mass ejections and corotating interaction regions. The solar wind ion precipitation appears localized and/or intermittent, consistent with previous measurements. Precipitation events are less frequent and the precipitating fluxes do not increase during pressure pulse encounters. During pressure pulses the occurrence frequency of observed proton precipitation events is reduced by a factor ~3 and for He 2+ events the occurrence frequency is reduced by a factor ~2. One explanation is that during pressure pulse periods, the mass loading of the solar wind plasma increases due to a deeper penetration of the interplanetary magnetic flux tubes into the ionosphere. The associated decrease of the solar wind speed thus increases the pile-up of the interplanetary magnetic field on the dayside of the planet. The magnetic barrier becomes thicker in terms of solar wind ion gyroradii, causing the observed reduction of H + /He 2+ precipitations.

Description: [1]  We present THEMIS observations of a " Spontaneous Hot Flow Anomaly" (SHFA) upstream from the pre-noon bow shock at 0431 UT on August 12, 2007. Although the SHFA exhibited the greatly heated and deflected solar wind plasmas used to identify hot flow anomalies (HFAs), it did not result from the standard mechanism invoked for the formation of HFAs, namely the interaction of an interplanetary magnetic field (IMF) discontinuity with the bow shock. We employ THEMIS A, B, C, and D observations to describe the evolution of the event from a proto-SHFA exhibiting regions of depressed magnetic field strength and density but little evidence for plasma heating or flow deflection, to a well-developed SHFA further downstream. These observations show that SHFA can be generated without the presence of an IMF discontinuity and are therefore a new category of HFAs.

Description: In the course of investigations relating to magnesia oxysulfate cement the basic magnesium salt hydrate 3Mg(OH) 2 · MgSO 4 · 8H 2 O (3–1–8 phase) was found as a metastable phase in the system Mg(OH) 2 -MgSO 4 -H 2 O at room temperature (the 5–1–2 phase is the stable phase) and was characterized by thermal analysis, Raman spectroscopy, and X-ray powder diffraction. The complex crystal structure of the 3–1–8 phase was determined from high resolution laboratory X-ray powder diffraction data [space group C 2/ c , Z = 4, a = 7.8956(1) Å, b = 9.8302(2) Å, c = 20.1769(2) Å, β = 96.2147(16)°, and V = 1556.84(4) Å 3 ]. In the crystal structure of the 3–1–8 phase, parallel double chains of edge-linked distorted Mg(OH 2 ) 2 (OH) 4 octahedra run along [–110] and [110] direction forming a pattern of crossed rods. Isolated SO 4 tetrahedra and interstitial water molecules separate the stacks of parallel double chains.

Description: [1]  The two primary methods responsible for solar wind magnetosphere coupling are magnetic reconnection and the viscous interaction. The viscous interaction is generated due to the antisunward dragging of plasma inside the magnetopause by the plasma flowing in the magnetosheath, creating a return flow deeper inside the magnetosphere and producing a circulation pattern. This viscous circulation pattern is mapped into the ionosphere via magnetic field lines, which results in ionospheric electric field in the non-rotating Earth's frame. We measure this interaction in terms of an electric potential, the viscous potential. In this paper, we use the results obtained from the LFM simulation model during periods of purely northward IMF for different solar wind velocity and ionospheric conductivity, showing a reduction of the viscous potential with increasing magnitude of northward IMF. The viscous potential is found to settle around 5-10 kV for large + B z values. The decrease in viscous potential was found to be associated with a weak or non-existent sunward plasma flow in the nightside plasmasheet. Instead, the return flow to the dayside occurs at high latitudes and is associated with the reconnection topology and dynamics that occur during northward IMF periods. We also show that the magnetosphere remains closed during purely northward IMF, except for two small regions-one on each hemisphere, where the magnetic reconnection occur. We argue that the reduction of the viscous potential is due to a reduction of the velocity shear across the magnetopause and the lack of sunward convection in the equatorial tail.

Description: [1]  We present an analytical model of the Poynting flux that is generated by the interaction between the plume of Enceladus and Saturn's magnetospheric plasma. Our purpose is to analyze the influence of two key elements of Enceladus’ magnetospheric interaction on the electromagnetic energy radiated away in the moon's Alfvén wings. First, the north-south asymmetry of the obstacle generates a system of hemisphere coupling currents which allows a transport of electromagnetic energy into Saturn's northern hemisphere, even if the field-aligned currents connecting to the plume are completely blocked at the non-conducting icy crust of Enceladus. Second, the presence of electron-absorbing dust grains within the plume was recently found to drastically modify the electromagnetic field configuration within Enceladus’ Alfvén wings (Anti-Hall effect), thereby also altering the energy flux radiated away from the interaction region. By systematically studying the impact of varying strengths of the hemisphere coupling currents and varying electron absorption fractions on the energy flux, we come to the following conclusions: (1) The integrated Poynting flux into Saturn's southern hemisphere always exceeds the integrated flux into the northern hemisphere. In particular, the power transmitted towards the south may become several orders of magnitude larger than the power transmitted towards the north. (2) The search for Enceladus’ auroral footprint has so far mainly focused on Saturn's northern hemisphere. However, based on the Poynting fluxes radiated away by the interaction, detections of the footprint should occur more likely in the giant planet's southern hemisphere, if no other far-field effects play a role. (3) Electron absorption by the dust grains within the plume makes a measurable contribution to the energy flux. Thus, changes in the brightness of the observed footprints cannot exclusively be ascribed to variations in the incident magnetospheric flow conditions or the neutral gas content of the plume, but variations in the properties of the dust component need to be taken into account as well.

Description: [1]  Suprathermal singly-charged molecular ions, O 2 + (at ~32 Da/e) and the Mass-28 ion group 28 M + (ions at ~28 Da/e, with possible contributions from C 2 H 5 + , HCNH + , N 2 + , and/or CO + ), are present throughout Saturn's ~4-20 Rs (1 Saturn radius, Rs = 60,268 km) near-equatorial magnetosphere from mid-2004 until mid-2012. These ~83-167 keV/e heavy ions measured by Cassini's CHarge-Energy-Mass Spectrometer, CHEMS, have long-term temporal profiles that differ from each other and differ relative to the dominant water group ions, W + (O + , OH + , H 2 O + , and H 3 O + ). O 2 + /W + , initially ~0.05, declined steadily until equinox in mid-2009 by a factor of ~6, and 28 M + /W + , initially ~0.007, declined similarly until early-2007 by a factor of ~2. The O 2 + /W + decline is consistent with Cassini's in-situ ring-ionosphere thermal ion measurements, and with proposed and modeled seasonal photolysis of Saturn's rings for thermal O 2 and O 2 + . The water ice dominated main rings and Enceladus plume depositions thereon are the two most likely O 2 + sources. Enceladus' dynamic plumes, though, have no known long-term dependence. After declining, O 2 + /W + and 28 M + /W + levels remained low until late-2011 when O 2 + /W + increased, but 28 M + /W + did not. The O 2 + /W + increase was steady and became statistically significant by mid-2012, indicating a clear increase after a decline, that is, a possibly delayed O 2 + “seasonal” recovery. Ring insolation is driven by solar UV flux which itself varies with the sun's 11-year activity cycle. The O 2 + /W + and 28 M + /W + declines are consistent with seasonal ring insolation. No O 2 + /W + response to the late-2008 solar-cycle UV minimum and recovery is evident. However, the O 2 + /W + recovery from the post-equinox baseline levels in late-2011 coincided with a strong solar UV enhancement. We suggest a scenario/framework in which the O 2 + observations can be understood.

Description: [1]  We analyze ion temperature data near 350 km altitude over the years 1966–2012 to seek explanations for three outstanding questions concerning the long-term cooling observed in the upper thermosphere: (1) why is the cooling so much larger than expected, (2) why has the cooling lasted so long, and (3) why is the thermospheric density response to the cooling so small? We speculate that gravity waves may cause this cooling and provide answers to these questions. Recent simulations have shown that gravity waves are expected to cool the upper thermosphere by an amount comparable to that observed over our data timeline. A gravity-wave proxy formed from the non-tidal fluctuations in temperature shows a positive long-term trend throughout its timeline, consistent with the increasing cooling observed. The time scales of the long-term trend and its decadal fluctuations are characteristic of the ocean, not the atmosphere. We suggest that the following scenario may explain these behaviors: (a) the climate regime shift of 1976–1977 launched slow Rossby waves across the oceans which continue to propagate to this day, (b) winds over this increasingly corrugated ocean have launched increasing fluxes of gravity waves into the atmosphere, (c) these increasing fluxes of gravity waves have propagated to the thermosphere to produced increasing amounts of cooling. The strong thermospheric cooling seen would be expected to produce thermospheric density declines much larger than those observed via satellite drag. These temperature and density results would be compatible if the turbopause were lowered 4 km over the time span of observations.

Description: The cover picture shows the synthesis and the molecular structure of a zwitterionic [4.3.0]-bicyclic aluminum-phosphorus compound with annulated C 3 P 2 and Al 2 C 2 PH heterocycles and a 3c-2e Al–H–Al bond. Treatment of the dialkynylphosphine Mes–P(–C=C–CMe 3 ) 2 ( 1 ) with diethylaluminum hydride ( 2 ) in an equimolar ratio afforded a mixture of compounds, in which a [3.2.0]-bicyclic compound 3 with annulated fourmembered AlC 2 P and five-membered P 2 C 3 heterocycles could be identified by NMR spectroscopy. Excess of the hydride 2 yielded small quantities of the zwitterionic [4.3.0]-bicyclic compound 4 , which formally resulted from the unique insertion of a diethylaluminum hydride molecule into the Al–C(vinyl) bond of the strained fourmembered heterocycle of 3 . A six-membered ring is formed which contains an Al–H–Al 3c-2e bond. More details can be found in the Article by Werner Uhl et al. on page 1181 ff.

Description: Using the bis(pyrazolyl)pyridinylmethane ligand α,α,α-bis(1-pyrazolyl)(2-pyridinyl)toluene {(ph)C(pz) 2 (py)} for bioinorganic inspired coordination chemistry studies, we synthesised and structurally characterised three monofacial complexes [{(ph)C(pz) 2 (py)}CoCl 2 ] ( C1 ), [{(ph)C(pz) 2 (py)}CuCl 2 ] ( C2 ), [{(ph)C(pz) 2 (py)}ZnCl 2 ] ( C3 ) and the binuclear halogenido-bridged complexes [{(ph)C(pz) 2 (py)} 2 (μ-Cl) 2 Fe 2 Cl 2 ] ( C4 ) and [{(ph)C(pz) 2 (py)} 2 (μ-Br) 2 Cu 2 Br 2 ] ( C5 ). In four of these complexes, severe disorders between pyrazolyl and pyridinyl donor groups are observed such that bis(pyrazolyl) and (pyrazolyl)(pyridinyl) coordination modes are concomitantly found. The donor competition is dissected by DFT calculation of the energy differences between the two coordination modes and NBO analysis of the donor situation. The pyrazolyl units provide with more donor strength although pyridine is considerably more basic.

Description: Metal ions poisoning can result from environmental factors, intentional action, or disruption of homeostasis. Although the origin of toxicity may be different, the treatment is similar. Chelation therapy aims to remove the excess of metal ions from tissues to stop further damage of cells. For almost every metal ion, molecules that are able to bind it and remove from the human body are known. Over the years some new chelating agents were discovered and introduced into clinical treatment. In this paper we have focused on typical chelators for metal ions, both essential and toxic for humans. The treatment of poisoning caused by essential metal ions is hard due to the risk of removing them from the biologically relevant molecules (e.g. enzymes). Acute metal ions poisoning is rather rare, so the development of chelators for such cases are historical, but prolonged toxicity of, especially, essential metal ions is extensively studied.

Description: The reactions of [Os(NO)Cl 5 ] 2– with glycine (GlyH), picolinic acid (PicoH), L -proline ( L -ProH) and D -proline ( D -ProH) afforded four novel complexes of the general formula [Os(NO)Cl 3 (AA)] – , where AA = Gly, Pico, L -Pro and D -Pro, respectively. X-ray diffraction studies have revealed that in all cases the same isomer type from three theoretically possible, has been isolated, namely mer (Cl), trans (NO, O)-[Os(NO)Cl 3 (AA)] – . Spectroscopic and electrochemical properties, behavior in aqueous solution and antiproliferative activity in three human cancer cell lines are also reported.

Description: The electron distributions in position and in momentum space of the hcp metals magnesium and zinc are investigated experimentally and compared to results of quantum-chemical calculations. Furthermore, a survey is given on recent analyses of the bonding properties of zinc and cadmium, using the method of increments. The experimental deformation densities were obtained by refining multipole models to X-ray diffraction data sets measured at 100 K with either Mo- K α (Mg) or Ag- K α (Zn) radiation. The final R F values (Valray/Jana2006) are 0.0028/0.0034 (Mg) and 0.0068/0.0068 (Zn). The differences to deformation densities obtained from periodic density functional calculations are discussed. The effect of dynamical electron correlation on the electron density was analyzed, using cluster models. Compton profiles were measured with 88.67 keV synchrotron radiation at beamline ID15B at the ESRF in Grenoble. Varied orientations of the samples allowed for probing the projected momentum distribution along the [100], [423] and [001] directions. Fourier transforms of the computed reciprocal form factor B ( r ) resulted in the corresponding theoretical Compton profiles. It is suggested that the anomalous hcp structure of zinc is favored by a kinetic balancing of the valence electrons, i.e. correlation mediated 4 s -3 d interactions.