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  • 1
    Publikationsdatum: 2016-06-17
    Beschreibung: Knowledge of solar wind conditions at Mars is often necessary to study the planet's magnetospheric and ionospheric dynamics. With no continuous upstream solar wind monitor at Mars, studies have used a variety of methods to measure or predict Martian solar wind conditions. In situ measurements, when available, are preferred, but can often be limited in continuity or scope, and so studies have also utilized solar wind proxies, spacecraft flybys, and Earth-Mars alignment to provide solar wind context. Despite the importance of solar wind knowledge and the range of methods used to provide it, the use of solar wind models remains relatively unutilized. This study uses the WSA-ENLIL + Cone solar wind model to calculate solar wind parameters at Mars’ orbital location to provide a new approach to determining solar wind conditions at Mars. Comparisons of the model results with observations by the MAVEN spacecraft indicate that the WSA-ENLIL + Cone model can forecast solar wind conditions at Mars as accurately as it has predicted them historically at the Earth, although at Mars the model systematically mispredicts solar wind speed and density, likely a result of magnetogram calibration. Particular focus is placed on modeling the early March 2015 ICMEs that interacted with Mars. Despite the complexity of the ICMEs, the model accurately predicted the speed and arrival time of the ICME-driven interplanetary shock, although it underpredicted other solar wind parameters. These results suggest that solar wind models can be used to provide the necessary general context of the heliospheric conditions to planetary studies.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2015-11-07
    Beschreibung: The Mars Atmosphere and Volatile Evolution (MAVEN) mission, during the second of its Deep Dip campaigns, made comprehensive measurements of martian thermosphere and ionosphere composition, structure, and variability at altitudes down to ~130 kilometers in the subsolar region. This altitude range contains the diffusively separated upper atmosphere just above the well-mixed atmosphere, the layer of peak extreme ultraviolet heating and primary reservoir for atmospheric escape. In situ measurements of the upper atmosphere reveal previously unmeasured populations of neutral and charged particles, the homopause altitude at approximately 130 kilometers, and an unexpected level of variability both on an orbit-to-orbit basis and within individual orbits. These observations help constrain volatile escape processes controlled by thermosphere and ionosphere structure and variability.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bougher, S -- Jakosky, B -- Halekas, J -- Grebowsky, J -- Luhmann, J -- Mahaffy, P -- Connerney, J -- Eparvier, F -- Ergun, R -- Larson, D -- McFadden, J -- Mitchell, D -- Schneider, N -- Zurek, R -- Mazelle, C -- Andersson, L -- Andrews, D -- Baird, D -- Baker, D N -- Bell, J M -- Benna, M -- Brain, D -- Chaffin, M -- Chamberlin, P -- Chaufray, J-Y -- Clarke, J -- Collinson, G -- Combi, M -- Crary, F -- Cravens, T -- Crismani, M -- Curry, S -- Curtis, D -- Deighan, J -- Delory, G -- Dewey, R -- DiBraccio, G -- Dong, C -- Dong, Y -- Dunn, P -- Elrod, M -- England, S -- Eriksson, A -- Espley, J -- Evans, S -- Fang, X -- Fillingim, M -- Fortier, K -- Fowler, C M -- Fox, J -- Groller, H -- Guzewich, S -- Hara, T -- Harada, Y -- Holsclaw, G -- Jain, S K -- Jolitz, R -- Leblanc, F -- Lee, C O -- Lee, Y -- Lefevre, F -- Lillis, R -- Livi, R -- Lo, D -- Ma, Y -- Mayyasi, M -- McClintock, W -- McEnulty, T -- Modolo, R -- Montmessin, F -- Morooka, M -- Nagy, A -- Olsen, K -- Peterson, W -- Rahmati, A -- Ruhunusiri, S -- Russell, C T -- Sakai, S -- Sauvaud, J-A -- Seki, K -- Steckiewicz, M -- Stevens, M -- Stewart, A I F -- Stiepen, A -- Stone, S -- Tenishev, V -- Thiemann, E -- Tolson, R -- Toublanc, D -- Vogt, M -- Weber, T -- Withers, P -- Woods, T -- Yelle, R -- New York, N.Y. -- Science. 2015 Nov 6;350(6261):aad0459. doi: 10.1126/science.aad0459.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CLaSP Department, University of Michigan, Ann Arbor, MI, USA. bougher@umich.edu. ; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA. ; Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA. ; NASA/Goddard Space Flight Center, Greenbelt, MD, USA. ; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. ; CNRS/Institut de Recherche en Astrophysique et Planetologie, Toulouse, France. University Paul Sabatier, Toulouse, France. ; Swedish Institute of Space Physics, Kiruna, Sweden. ; NASA/Johnson Space Center, Houston, TX, USA. ; National Institute of Aerospace, Hampton, VA, USA. ; Laboratoire Atmospheres, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France. ; Department of Astronomy, Boston University, Boston, MA, USA. ; CLaSP Department, University of Michigan, Ann Arbor, MI, USA. ; Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA. ; Computational Physics, Springfield, VA, USA. ; Department of Physics, Wright State University, Fairborn, OH, USA. ; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA. ; Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA, USA. ; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi, Japan. ; Naval Research Laboratory, Washington, DC, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26542579" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2015-11-07
    Beschreibung: Planetary auroras reveal the complex interplay between an atmosphere and the surrounding plasma environment. We report the discovery of low-altitude, diffuse auroras spanning much of Mars' northern hemisphere, coincident with a solar energetic particle outburst. The Imaging Ultraviolet Spectrograph, a remote sensing instrument on the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, detected auroral emission in virtually all nightside observations for ~5 days, spanning nearly all geographic longitudes. Emission extended down to ~60 kilometer (km) altitude (1 microbar), deeper than confirmed at any other planet. Solar energetic particles were observed up to 200 kilo--electron volts; these particles are capable of penetrating down to the 60 km altitude. Given minimal magnetic fields over most of the planet, Mars is likely to exhibit auroras more globally than Earth.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schneider, N M -- Deighan, J I -- Jain, S K -- Stiepen, A -- Stewart, A I F -- Larson, D -- Mitchell, D L -- Mazelle, C -- Lee, C O -- Lillis, R J -- Evans, J S -- Brain, D -- Stevens, M H -- McClintock, W E -- Chaffin, M S -- Crismani, M -- Holsclaw, G M -- Lefevre, F -- Lo, D Y -- Clarke, J T -- Montmessin, F -- Jakosky, B M -- New York, N.Y. -- Science. 2015 Nov 6;350(6261):aad0313. doi: 10.1126/science.aad0313.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Boulder, CO 80303, USA. nick.schneider@lasp.colorado.edu. ; Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Boulder, CO 80303, USA. ; Space Sciences Lab, University of California, Berkeley, Berkeley, CA 94720, USA. ; Institut de Recherche en Astrophysique et Planetologie (IRAP), CNRS, Toulouse, France. University Paul Sabatier, IRAP, CNRS, Toulouse, France. ; Computational Physics, Inc, Springfield, VA 22151, USA. ; Space Science Division, Naval Research Laboratory, Washington, DC 20375, USA. ; Laboratoire Atmospheres, Milieux, Observations Spatiales, Institut Pierre Simon Laplace, Guyancourt, France. ; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. ; Center for Space Physics, Boston University, Boston, MA 02215, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26542577" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
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  • 4
    Publikationsdatum: 2015-11-07
    Beschreibung: Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere, ionosphere, and interactions with the Sun and solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes in the bow shock and magnetosheath, formation of widespread diffuse aurora, and enhancement of pick-up ions. Observations and models both show an enhancement in escape rate of ions to space during the event. Ion loss during solar events early in Mars history may have been a major contributor to the long-term evolution of the Mars atmosphere.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jakosky, B M -- Grebowsky, J M -- Luhmann, J G -- Connerney, J -- Eparvier, F -- Ergun, R -- Halekas, J -- Larson, D -- Mahaffy, P -- McFadden, J -- Mitchell, D F -- Schneider, N -- Zurek, R -- Bougher, S -- Brain, D -- Ma, Y J -- Mazelle, C -- Andersson, L -- Andrews, D -- Baird, D -- Baker, D -- Bell, J M -- Benna, M -- Chaffin, M -- Chamberlin, P -- Chaufray, Y-Y -- Clarke, J -- Collinson, G -- Combi, M -- Crary, F -- Cravens, T -- Crismani, M -- Curry, S -- Curtis, D -- Deighan, J -- Delory, G -- Dewey, R -- DiBraccio, G -- Dong, C -- Dong, Y -- Dunn, P -- Elrod, M -- England, S -- Eriksson, A -- Espley, J -- Evans, S -- Fang, X -- Fillingim, M -- Fortier, K -- Fowler, C M -- Fox, J -- Groller, H -- Guzewich, S -- Hara, T -- Harada, Y -- Holsclaw, G -- Jain, S K -- Jolitz, R -- Leblanc, F -- Lee, C O -- Lee, Y -- Lefevre, F -- Lillis, R -- Livi, R -- Lo, D -- Mayyasi, M -- McClintock, W -- McEnulty, T -- Modolo, R -- Montmessin, F -- Morooka, M -- Nagy, A -- Olsen, K -- Peterson, W -- Rahmati, A -- Ruhunusiri, S -- Russell, C T -- Sakai, S -- Sauvaud, J-A -- Seki, K -- Steckiewicz, M -- Stevens, M -- Stewart, A I F -- Stiepen, A -- Stone, S -- Tenishev, V -- Thiemann, E -- Tolson, R -- Toublanc, D -- Vogt, M -- Weber, T -- Withers, P -- Woods, T -- Yelle, R -- New York, N.Y. -- Science. 2015 Nov 6;350(6261):aad0210. doi: 10.1126/science.aad0210.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of Colorado, Boulder, CO, USA. bruce.jakosky@lasp.colorado.edu. ; NASA/Goddard Space Flight Center, Greenbelt, MD, USA. ; University of California at Berkeley, Berkeley, CA, USA. ; University of Colorado, Boulder, CO, USA. ; University of Iowa, Iowa City, IA, USA. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. ; University of Michigan, Ann Arbor, MI, USA. ; University of California at Los Angeles, Los Angeles, CA, USA. ; CNRS-Institut de Recherche en Astrophysique et Planetologie (IRAP), Toulouse, France. University Paul Sabatier, Toulouse, France. ; Swedish Institute of Space Physics, Uppsala, Sweden. ; NASA/Johnson Space Center, Houston, TX, USA. ; National Institute of Aerospace, Hampton, VA, USA. ; Laboratoire atmospheres, milieux et observations spatiales (LATMOS)-CNRS, Paris, France. ; Boston University, Boston, MA, USA. ; University of Kansas, Lawrence, KS, USA. ; Computational Physics, Inc., Boulder, CO, USA. ; Wright State University, Dayton, OH, USA. ; University of Arizona, Tucson, AZ, USA. ; Nagoya University, Nagoya, Japan. ; Naval Research Laboratory, Washington, DC, USA. ; North Carolina State University, Raleigh, NC, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26542576" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
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  • 5
    Publikationsdatum: 2017-08-31
    Beschreibung: Multipoint observations from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express and the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission reveal a dynamic response of the Martian ionosphere to abrupt variations in the upstream solar wind plasma. On 2 February 2017, MAVEN, located upstream from the Martian bow shock, encountered a CIR-related interplanetary shock with a sudden enhancement in the dynamic pressure. MARSIS, operating in the upper ionosphere at ∼478 km altitudes and ∼78 ∘ solar zenith angles, observed a sharp increase in the local magnetic field magnitude ∼1 min after the shock passage at MAVEN. The time lag is roughly consistent with the expected propagation time of a pressure pulse from the bow shock to the upper ionosphere at the fast magnetosonic speed. Subsequently, remote soundings recorded disturbed signatures of the topside ionosphere below Mars Express.
    Print ISSN: 0094-8276
    Digitale ISSN: 1944-8007
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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  • 6
    Publikationsdatum: 2017-03-02
    Beschreibung: The response of Mars to the major space weather events called Interplanetary Coronal Mass Ejections (ICMEs) is of interest for both general planetary solar wind interaction studies and related speculations on their evolutionary consequences-especially with respect to atmosphere escape. Various particle and field signatures of ICMEs have been observed on Phobos-2, Mars Global Surveyor (MGS), Mars Express (MEX), and now MAVEN. Of these, MAVEN's combined instrumentation and orbit geometry is particularly well-suited to characterize both the event drivers and their consequences. However, MAVEN has detected only moderate disturbances at Mars due in large part to the general weakness of the present solar cycle. Nevertheless, the strongest event observed by MAVEN in March 2015 provides an example illustrating how further insights can be gained from available models. Here we first look more closely at what previously run BATS-R-US MHD simulations of the combined MAVEN observations tell us about the March 2015 event consequences. We then use analogous models to infer those same responses, including magnetic field topology changes and ionospheric consequences, to a hypothetical extreme ICME at Mars based on STEREO-A measurements in July 2012. The results suggest how greatly enhanced, yet realistic, solar wind pressure, magnetic field, and convection electric field combine to produce strong magnetospheric coupling with important consequences for upper atmosphere and ionosphere energization.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
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    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1980-08-08
    Beschreibung: Calcium ion-selective microelectrodes made with Simon's neutral carrier were used to measure simultaneously sarcoplasmic Ca2+ activity (aiCa) and resting tension (Tr) of rabbit ventricular muscle during reduction and restoration of external sodium ion concentration, [Na]0. Under the same experimental conditions the change in contractile tension (Ta) also measured. In resting muscle the aiCa was 38 +/- 17 nanomolar (mean +/- standard deviation; N = 10). The reduction of [Na]O from 153 to 20 millimolar led to about a threefold increase in aiCa with parallel increases in Tr and Ta. The time course of the change in aiCa was similar to that of the changes in Tr and Ta. The results are consistent with an important role of the sodium-calcium exchange system for regulating sarcoplasmic Ca2+ activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lee, C O -- Uhm, D Y -- Dresdner, K -- New York, N.Y. -- Science. 1980 Aug 8;209(4457):699-701.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7394527" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Biological Transport/drug effects ; Calcium/*metabolism ; Heart Ventricles/metabolism ; Kinetics ; Membrane Potentials/drug effects ; Microelectrodes ; Myocardium/*metabolism ; Rabbits ; Sarcoplasmic Reticulum/drug effects/*metabolism ; Sodium/*metabolism/pharmacology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 2017-12-27
    Beschreibung: Normal solar wind flows and intense solar transient events interact directly with the upper Martian atmosphere due to the absence of an intrinsic global planetary magnetic field. Since the launch of the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, there are now new means to directly observe solar wind parameters at the planet's orbital location for limited time spans. Due to MAVEN's highly elliptical orbit, in situ measurements cannot be taken while MAVEN is inside Mars' magnetosheath. To model solar wind conditions during these atmospheric and magnetospheric passages, this research project utilized the solar wind forecasting capabilities of the WSA-ENLIL+Cone model. The model was used to simulate solar wind parameters which included magnetic field magnitude, plasma particle density, dynamic pressure, proton temperature, and velocity during a four Carrington rotation-long segment. An additional simulation that lasted 18 Carrington rotations was then conducted. The precision of each simulation was examined for intervals when MAVEN was in the upstream solar wind, i.e., with no exospheric or magnetospheric phenomena altering in situ measurements. It was determined that generalized, extensive simulations have comparable prediction capabilities as shorter, more comprehensive simulations. Generally, this study aimed to quantify the loss of detail in long-term simulations and to determine if extended simulations can provide accurate, continuous upstream solar wind conditions when there is a lack of in situ measurements.
    Print ISSN: 1539-4964
    Digitale ISSN: 1542-7390
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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  • 9
    Publikationsdatum: 2017-04-30
    Beschreibung: Solar energetic particles (SEPs) can precipitate directly into the atmospheres of weakly magnetized planets, causing increased ionization, heating, and altered neutral chemistry. However, strong localized crustal magnetism at Mars can deflect energetic charged particles and reduce precipitation. In order to quantify these effects, we have developed a model of proton transport and energy deposition in spatially varying magnetic fields, called Atmospheric Scattering of Protons and Energetic Neutrals (ASPEN). We benchmark the model's particle tracing algorithm, collisional physics, and heating rates, comparing against previously published work in the latter two cases. We find that energetic non-relativistic protons precipitating in proximity to a crustal field anomaly will primarily deposit energy at either their stopping altitude or magnetic reflection altitude. We compared atmospheric ionization in the presence and absence of crustal magnetic fields at 50° S and 182° E during the peak flux of the 29 October 2003 “Halloween storm” SEP event. The presence of crustal magnetic fields reduced total ionization by ~30% but caused ionization to occur over a wider geographic area.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2013-08-04
    Beschreibung: [1]  The radial alignment of ACE and Ulysses in February 2004 and August 2007 provided us with unprecedented opportunities to study the radial evolution of planar magnetic structures in 3 corotating interaction regions (CIRs). The in-situ observations are compared with results from an analytical and a numerical model of CIRs (Lee, 2000; Odstrcil, 2003). We find that: 1) All 3 CIRs' meridional tilt retained its North/South orientation at ACE and Ulysses, but the evolution was not systematic. Further, the model results of CIR meridional tilt do not agree with observations. 2) All 3 CIRs rotated azimuthally with the Parker spiral as expected, however model results only describe this behavior quantitatively for 1 CIR. 3) For all 3 CIRs, the solar wind deflection angles were predicted by the coupled solar corona-solar wind models, Wang-Sheely-Arge (WSA)-Enlil and MHD Around a Sphere (MAS)-Enlil, but neither model reproduced the observed planar magnetic structures. 4) The WSA-Enlil results of azimuthal magnetic field orientation are in better agreement with observations than those based on the MAS-Enlil. We suggest that the evolution of meridional tilt from ACE to Ulysses did not agree with projections because the parent coronal holes were highly structured. We also suggest that observations of azimuthal tilt do not agree with the model results because the models may underestimate transverse flows, whereas in reality, these flows could affect the observed azimuthal tilt of the CIR. The local orientation of PMSs within CIRs may also be distorted by transients, but their effect is unclear.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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