HR: 11:00h
AN: SM52A-03    [Abstracts]
TI: Superposed Epoch Analysis of Cold, Dense Plasma Sheet Access to Geosynchronous Orbit
AU: * Lavraud, B
EM: lavraud@lanl.gov
AF: Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AU: Denton, M H
EM: mdenton@lanl.gov
AF: Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AU: Thomsen, M F
EM: mthomsen@lanl.gov
AF: Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AU: Borovsky, J E
EM: jborovsky@lanl.gov
AF: Space Science and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AB: We report on the occurrence of cold, dense plasma access to geosynchronous orbit. We performed a superposed epoch analysis of 1952 events of dense (> 2 /cc at onset) plasma observed by the MPA instruments onboard the Los Alamos satellites, for the period 1990-2002. The results show the temporal evolution of various plasma parameters as a function of local time. We show that dense plasma access to geosynchronous orbit mostly occurs near local midnight. Such access is also observed at slightly later times on the dawnside of geosynchronous orbit. We demonstrate that this latter population is, however, not the result of the dawnward transport of the population detected near midnight. The dense plasma population observed in the midnight region is shown to be freshly injected from the mid-tail region, colder than the typical plasma sheet and composed of a relatively small O+ component. This population is thus probably the result of cold, dense plasma sheet (CDPS) injection from the mid-tail region. The population observed on the dawnside of geosynchronous orbit is possibly the result of inward motion of the low-latitude boundary layer (LLBL). The observation of an enhanced Kp index around the arrival of the CDPS at geosynchronous orbit shows that the inward transport of these populations is allowed by an enhanced magnetospheric convection.
DE: 2740 Magnetospheric configuration and dynamics
DE: 2760 Plasma convection
DE: 2764 Plasma sheet
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly