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  • 1
    Electronic Resource
    Electronic Resource
    High-beta plasma blobs in the morningside plasma sheet (1999)
    Springer
    Annales geophysicae 17 (1999), S. 1592-1601 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (plasma convection ; plasma sheet ; plasma waves and instabilities)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Equator-S frequently encountered, i.e. on 30%0of the orbits between 1 March and 17 April 1998, strong variations of the magnetic field strength of typically 5–15-min duration outside about 9RE during the late-night/early-morning hours. Very high-plasma beta values were found, varying between 1 and 10 or more. Close conjunctions between Equator-S and Geotail revealed the spatial structure of these “plasma blobs” and their lifetime. They are typically 5–10° wide in longitude and have an antisymmetric plasma or magnetic pressure distribution with respect to the equator, while being altogether low-latitude phenomena (〈15°). They drift slowly sunward, exchange plasma across the equator and have a lifetime of at least 15–30 min. While their spatial structure may be due to some sort of mirror instability, little is known about the origin of the high-beta plasma. It is speculated that the morningside boundary layer somewhat further tailward may be the source of this plasma. This would be consistent with the preference of the plasma blobs to occur during quiet conditions, although they are also found during substorm periods. The relation to auroral phenomena in the morningside oval is uncertain. The energy deposition may be mostly too weak to generate a visible signature. However, patchy aurora remains a candidate for more disturbed periods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-999-1592-1
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  • 2
    Electronic Resource
    Electronic Resource
    Substorm observations in the early morning sector with Equator-S and Geotail (1999)
    Springer
    Annales geophysicae 17 (1999), S. 1602-1610 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (magnetospheric configuration and dynamics ; plasma sheet ; storms and substorms)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Data from Equator-S and Geotail are used to study the dynamics of the plasma sheet observed during a substorm with multiple intensifications on 25 April 1998, when both spacecraft were located in the early morning sector (03–04 MLT) at a radial distance of 10–11 RE. In association with the onset of a poleward expansion of the aurora and the westward electrojet in the premidnight and midnight sector, both satellites in the morning sector observed plasma sheet thinning and changes toward a more tail-like field configuration. During the subsequent poleward expansion in a wider local time sector (20−04 MLT), on the other hand, the magnetic field configuration at both satellites changed into a more dipolar configuration and both satellites encountered again the hot plasma sheet. High-speed plasma flows with velocities of up to 600 km/s and lasting 2–5 min were observed in the plasma sheet and near its boundary during this plasma sheet expansion. These high-speed flows included significant dawn-dusk flows and had a shear structure. They may have been produced by an induced electric field at the local dipolarization region and/or by an enhanced pressure gradient associated with the injection in the midnight plasma sheet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-999-1602-3
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  • 3
    Electronic Resource
    Electronic Resource
    Observations of flux rope – associated particle bursts with GEOTAIL in the distant tail (1997)
    Springer
    Annales geophysicae 15 (1997), S. 1515-1531 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric configuration and dynamics ; Magnetotail
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Geotail energetic particle, magnetic field data and plasma observations (EPIC, MGF and CPI experiments) have been examined for a number of energetic particle bursts in the distant tail (120Re 〈 |XGSM| 〈 130 Re), associated with moving magnetic field structures, following substorm onsets. The features obtained from this data analysis are consistent with the distant magnetotail dynamics determined first by ISEE3 observations and explained in terms of the neutral line model. At the onset of the bursts, before plasma sheet entrance, energetic electrons appear as a field-aligned beam flowing in the tailward direction, followed by anisotro-pic ions. Within the flux rope region, suprathermal ions exhibit a convective anisotropy, which allows determination of the plasma flow velocity, assuming that the anisotropy arises from the Compton-Getting effect. The velocities thus determined in the plasma sheet are estimated to be 200–650 km/s, and compare favourably with the velocities derived from the CPI electron and proton experiment. The estimated length of magnetic field structures varies between 28 and 56 Re and depends on the strength of the westward electrojet intensification. Finally, the three structures reported here show clear magnetic field signatures of flux rope topology. The existence of a strong magnetic field aligned approximately along the Y-axis and centred on the north-to-south excursion of the field, and the bipolar signature in both By and/or Bz components, is consistent with the existence of closed field lines extending from Earth and wrapping around the core of the flux rope structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-997-1515-y
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  • 4
    Electronic Resource
    Electronic Resource
    Spatial structure of the plasma sheet boundary layer at distances greater than 180 RE as derived from energetic particle measurements on GEOTAIL (1997)
    Springer
    Annales geophysicae 15 (1997), S. 1246-1256 
    Details
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We have analyzed the onsets of energetic particle bursts detected by the ICS and STICS sensors of the EPIC instrument on board the GEOTAIL spacecraft in the deep magnetotail (i.e., at distances greater than 180 RK). Such bursts are commonly observed at the plasma-sheet boundary layer (PSBL) and are highly collimated along the magnetic field. The bursts display a normal velocity dispersion (i.e., the higher-speed particles are seen first, while the progressively lower speed particles are seen later) when observed upon entry of the spacecraft from the magnetotail lobes into the plasma sheet. Upon exit from the plasma sheet a reverse velocity dispersion is observed (i.e., lower-speed particles disappear first and higher-speed particles disappear last). Three major findings are as follows. First, the tailward-jetting energetic particle populations of the distant-tail plasma sheet display an energy layering: the energetic electrons stream along open PSBL field lines with peak fluxes at the lobes. Energetic protons occupy the next layer, and as the spacecraft moves towards the neutral sheet progressively decreasing energies are encountered systematically. These plasma-sheet layers display spatial symmetry, with the plane of symmetry the neutral sheet. Second, if we consider the same energy level of energetic particles, then the H ‘ layer is confined within that of the energetic electron, the He++ layer is confined within that of the proton, and the oxygen layer is confined within the alpha particle layer. Third, whenever the energetic electrons show higher fluxes inside the plasma sheet as compared to those at the boundary layer, their angular distribution is isotropic irrespective of the Earthward or tailward character of fluxes, suggesting a closed field line topology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-997-1246-0
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  • 5
    Electronic Resource
    Electronic Resource
    Magnetotail response during a strong substorm as observed by GEOTAIL in the distant tail (1998)
    Springer
    Annales geophysicae 16 (1998), S. 528-541 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (magnetospheric configuration and dynamics; magnetotail)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Simultaneous energetic particle and magnetic field observations from the GEOTAIL spacecraft in the distant tail (XGSM ≈ -150 Re) have been analysed to study the response of the Earth’s magnetotail during a strong substorm (AE ⩽ 680 nT). At geosynchronous altitude, LANL spacecraft recorded three electron injections between 0030 UT and 0130 UT, which correspond to onsets observed on the ground at Kiruna Ground Observatory. The Earth’s magnetotail responded to this substorm with the ejection of five plasmoids, whose size decreases from one plasmoid to the next. Since the type of magnetic structure detected by a spacecraft residing the lobes, depends on the Z extent of the structure passing underneath the spacecraft, GEOTAIL is first engulfed by a plasmoid structure; six minutes later it detects a boundary layer plasmoid (BLP) and finally at the recovery phase of the substorm GEOTAIL observes three travelling compression regions (TCRs). The time-of-flight (TOF) speed of these magnetic structures was estimated to range between 510 km/s and 620 km/s. The length of these individual plasmoids was calculated to be between 28 Re and 56 Re. The principal axis analysis performed on the magnetic field during the TCR encountered, has confirmed that GEOTAIL observed a 2-D perturbation in the X-Z plane due to the passage of a plasmoid underneath. The first large plasmoid that engulfed GEOTAIL was much more complicated in nature probably due to the external, variable draped field lines associated with high beta plasma sheet and the PSBL flux tubes surrounding the plasmoid. From the analysis of the energetic particle angular distribution, evidence was found that ions were accelerated from the distant X-line at the onset of the burst associated with the first magnetic structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-0528-5
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  • 6
    Electronic Resource
    Electronic Resource
    Properties and origin of energetic particles at the duskside of the Earth’s magnetosheath throughout a great storm (1999)
    Springer
    Annales geophysicae 17 (1999), S. 1121-1133 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (magnetosheath; magnetotail boundary layers; storms and substorms)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We study an interval of 56 h on January 16 to 18, 1995, during which the GEOTAIL spacecraft traversed the duskside magnetosheath from X ≅ −15 to −40 RE and the EPIC/ICS and EPIC/STICS sensors sporadically detected tens of energetic particle bursts. This interval coincides with the expansion and growth of a great geomagnetic storm. The flux bursts are strongly dependent on the magnetic field orientation. They switch on whenever the Bz component approaches zero (Bz ≅ 0 nT). We strongly suggest a magnetospheric origin for the energetic ions and electrons streaming along these “exodus channels”. The time profiles for energetic protons and “tracer” O+ ions are nearly identical, which suggests a common source. We suggest that the particles leak out of the magnetosphere all the time and that when the magnetosheath magnetic field connects the spacecraft to the magnetotail, they stream away to be observed by the GEOTAIL sensors. The energetic electron fluxes are not observed as commonly as the ions, indicating that their source is more limited in extent. In one case study the magnetosheath magnetic field lines are draped around the magnetopause within the YZ plane and a dispersed structure for peak fluxes of different species is detected and interpreted as evidence for energetic electrons leaking out from the dawn LLBL and then being channelled along the draped magnetic field lines over the magnetopause. Protons leak from the equatorial dusk LLBL and this spatial differentiation between electron and proton sources results in the observed dispersion. A gradient of energetic proton intensities toward the ZGSM= 0 plane is inferred. There is a permanent layer of energetic particles adjacent to the magnetosheath during this interval in which the dominant component of the magnetic field was Bz.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-999-1121-2
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  • 7
    Electronic Resource
    Electronic Resource
    A Particular Geomagnetic Daily Variation ( Sq p ) in the Polar Regions on Geomagnetically Quiet Days (1962)
    [s.l.] : Nature Publishing Group
    Nature 195 (1962), S. 555-557 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A PRELIMINARY investigation of geomagnetic variation in the antarctic region1 has shown that the geomagnetic daily variation field, Sq, on quiet days in the dark polar region, is almost an extension of the well-known Sq -field in temperate latitudes, Sq0, but in the sun-lit polar region, a ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/195555a0
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  • 8
    Electronic Resource
    Electronic Resource
    Protein kinase c may regulate resting anion conductance in vascular smooth muscle cells
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 155 (1988), S. 882-889 
    Details
    ISSN: 0006-291X
    Keywords: [abr] H7; 1-(5-Isoquinolinesulfonyl)-2-methyl-piperazine dihydrochloride ; [abr] HEPES; N-2-hydroxgethylpiperazine-N'-2-ethanesulfonic acid
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0006-291X(88)80578-3
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  • 9
    Electronic Resource
    Electronic Resource
    Protein kinase c may regulate resting anion conductance in vascular smooth muscle cells
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 155 (1988), S. 882-889 
    Details
    ISSN: 0006-291X
    Keywords: [abr] H7; 1-(5-Isoquinolinesulfonyl)-2-methyl-piperazine dihydrochloride ; [abr] HEPES; N-2-hydroxgethylpiperazine-N'-2-ethanesulfonic acid
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0006-291X(88)80578-3
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  • 10
    Electronic Resource
    Electronic Resource
    Extended magnetic reconnection at the Earth's magnetopause from detection of bi-directional jets (2000)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 404 (2000), S. 848-850 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Magnetic reconnection is a process that converts magnetic energy into bi-directional plasma jets; it is believed to be the dominant process by which solar-wind energy enters the Earth's magnetosphere. This energy is subsequently dissipated by magnetic storms and aurorae. Previous ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35009050
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