Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 30, 379-387, 2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
Regular paper
22 Feb 2012
Global magnetospheric response to an interplanetary shock: THEMIS observations
H. Zhang1, D. G. Sibeck2, Q.-G. Zong3,4, J. P. McFadden5, D. Larson5, K.-H. Glassmeier6, and V. Angelopoulos7 1Geophysical Institute, University of Alaska Fairbanks, AK, USA
2NASA Goddard Space Flight Center, Greenbelt, MD, USA
3Center for Atmospheric Research, University of Massachusetts, Lowell, USA
4Institute of Space Physics and Applied Technology, Peking University, Beijing, China
5Space Sciences Laboratory, University of California, Berkeley, CA, USA
6Institute for Geopysics and Extraterrestrial Physics, TU Braunschweig, Germany
7IGPP/ESS UCLA, Los Angeles, CA 90095-1567, USA
Abstract. We investigate the global response of the geospace plasma environment to an interplanetary (IP) shock at ~02:24 UT on 28 May 2008 from multiple THEMIS spacecraft observations in the magnetosheath (THEMIS B and C), the mid-afternoon magnetosphere (THEMIS A), and the dusk magnetosphere (THEMIS D and E). The interaction of the transmitted IP shock with the magnetosphere has global effects. Consequently, it can affect geospace plasma significantly. After interacting with the bow shock, the IP shock transmitted a fast shock and a discontinuity which propagated through the magnetosheath toward the Earth at speeds of 301 km s−1 and 137 km s−1, respectively. THEMIS A observations indicate that the IP shock changed the properties of a plasmaspheric plume significantly. The plasmaspheric plume density increased rapidly from 10 to 100 cm−3 in 4 min and the ion distribution changed from an isotropic to a strongly anisotropic distribution. Electromagnetic ion cyclotron (EMIC) waves observed by THEMIS A are most likely excited by the anisotropic ion distributions caused by the IP shock impact. THEMIS A, but not D or E, observed a plasmaspheric plume in the dayside magnetosphere. Multiple spacecraft observations indicate that the dawn-side edge of the plasmaspheric plume was located between THEMIS A and D (or E).

Citation: Zhang, H., Sibeck, D. G., Zong, Q.-G., McFadden, J. P., Larson, D., Glassmeier, K.-H., and Angelopoulos, V.: Global magnetospheric response to an interplanetary shock: THEMIS observations, Ann. Geophys., 30, 379-387,, 2012.
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