HR: 1340h
AN: SM23A-1194 [Abstracts]
TI: Transition From Cold, Dense to Hot, Tenuous Plasma Sheet in the Near-Earth Magnetotail
AU: * Lee, E
EM: eslee@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, 7 Gauss way, Berkeley, CA 94720,
United States
AU: Parks, G K
EM: parks@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, 7 Gauss way, Berkeley, CA 94720,
United States
AU: Wilber, M
EM: wilber@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, 7 Gauss way, Berkeley, CA 94720,
United States
AU: Lin, N
EM: eslee@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, 7 Gauss way, Berkeley, CA 94720,
United States
AB:
It has been reported that sometimes the plasma sheet in the magnetotail consists of cold, dense ions, especially
during northward interplanetary magnetic field (IMF) periods. However, the mechanism explaining the formation
of the cold, dense plasma sheet is not yet understood. In this study we will present multi-spacecraft observations
showing transition of plasma sheet from cold, dense to hot, tenuous status in the near-Earth magnetotail. The
transition tends to occur very rapidly, in less than 1 min. Before the transition, the ion density is typically ~1
cm-3, and the temperature ~1 keV. After the transition, the ion density drops to ~0.3 cm-3,
while the temperature increases to ~2.5 keV. The transition boundary can be quite far from the flank
magnetopause and low latitude boundary layer (LLBL). For example, transition can be observed in the vicinity of
the central plasma sheet (|Bx| < 10 nT) at ~(-17.8, -7.06, 1.71 RE GSM). One interesting feature
is that the transition is usually accompanied by sudden increase of the Bz component. The electron
measurements also show same transitional features as the ions. These observations suggest that the near-
Earth plasma sheet may consist of separate regions with different plasmas and magnetic field configurations.
DE: 2744 Magnetotail
DE: 2748 Magnetotail boundary layers
DE: 2764 Plasma sheet
DE: 7846 Plasma energization
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting