HR: 0830h
AN: SM21B-0203    [PDF]
TI: The structure of the plasma sheet under northward IMF
AU: * Fujimoto, M
EM: fujimoto@geo.titech.ac.jp
AF: Dept. Earth Planet. Sci., TITECH, 2-12-1 Ookayama, Meguro, Tokyo, 152-8551 Japan
AU: Mukai, T
EM: mukai@stp.isas.ac.jp
AF: Inst. Space and Astronau. Sci., 3-1-1- Yoshinodai, Sagamihara, Kanagawa, 229-8510 Japan
AU: Kokubun, S
EM: kokubun@geo.titech.ac.jp
AF: Dept. Earth Planet. Sci., TITECH, 2-12-1 Ookayama, Meguro, Tokyo, 152-8551 Japan
AB: The structure of the plasma sheet under northward IMF is studied by data from the Geotail spacecraft. The plasma sheet is known to become cold and dense (T $<$ 2 keV, n $>$ 1 ${\rm cm}^{-3}$) during extended northward IMF periods. We show that such cold-dense ions (CDIs) appear at $| Y_{gsm} | $ $>$ 10 $R_e$, that is, 10 $R_e$ off the tail axis to both flanks. CDIs on the dawnside have higher temperatures and some reach the upper-limit of 2 keV that we use to select CDIs. These CDIs having the highest temperature are distributed at the dawnside plasma sheet inner-edge (R $<$ 15 $R_e$) and is connected to the hot-dense ions (HDIs: T $>$ 2 keV, n $>$ 1 ${\rm cm}^{-3}$) in the further inner region. A survey shows that HDIs under nominal solar wind dynamic pressure appear mostly in the dawnside inner-magnetosphere during extended northward IMF intervals. Both results point to the idea that HDIs are the inner-magnetosphere extension of dawnside CDIs, while such a partner to the duskside CDIs cannot be identified. This structure of the plasma sheet suggests that there is significant dawn-dusk asymmetry in heating and transport in the magnetotail under northward IMF.
DE: 7859 Transport processes
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting