| Volumes and Issues Contents of Issue 9 |
www.ann-geophys.net/25/2069/2007/
doi:10.5194/angeo-25-2069-2007
© European Geosciences Union 2007
Origin of temperature anisotropies in the cold plasma sheet: Geotail observations around the Kelvin-Helmholtz vortices
1School of Science, The University of Tokyo, Tokyo 113-0033, Japan
2ISAS/JAXA, Kanagawa 229-8510, Japan
3Institute of Statistical Mathematics, Tokyo 106-8569, Japan
4JAXA, Tokyo 100-8260, Japan
Abstract. To further our understanding of the solar wind entry across the magnetopause under northward IMF, we perform a case study of a duskside Kelvin-Helmholtz (KH) vortex event on 24 March 1995. We have found that the protons consist of two separate (cold and hot) components in the magnetosphere-like region inside the KH vortical structure. The cold proton component occasionally consisted of counter-streaming beams near the current layer in the KH vortical structure. Low-energy bidirectional electron beams or flat-topped electron distribution functions in the direction along the local magnetic field were apparent on the magnetosphere side of the current layer. We discuss that the bidirectionality of the electrons and the cold proton component implies magnetic reconnection inside the KH vortical structure. In addition, we suggest selective heating of electrons inside the vortical structure via wave-particle interactions. Comparing temperatures in the magnetosphere-like region inside the vortical structure with those in the cold plasma sheet, we show that further heating of both the electrons and the cold proton component is taking place in the cold plasma sheet or on the way from the vortices to the cold plasma sheet.
Full Article (PDF, 9267 KB)
Citation: Nishino, M. N., Fujimoto, M., Ueno, G., Mukai, T., and Saito, Y.: Origin of temperature anisotropies in the cold plasma sheet: Geotail observations around the Kelvin-Helmholtz vortices, Ann. Geophys., 25, 2069-2086, doi:10.5194/angeo-25-2069-2007, 2007. Bibtex EndNote Reference Manager XML
