HR: 1340h
AN: SM13A-1117    [Abstracts]
TI: Entropy Constraints on Particle Entry and Tail Transport from DMSP Measurements
AU: Lee, K
EM: kdlee@khu.ac.kr
AF: Department of Space Physics and Astronomy, Kyung Hee University, Yongin, Kyunggi, 449701, Korea, Republic of
AU: * Johnson, J R
EM: jrj@pppl.gov
AF: Princeton University, Plasma Physics Laboratory, Princeton, NJ 08543, United States
AU: Wing, S
EM: simon.wing@jhuapl.edu
AF: The Johns Hopkins University, Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723-6099, United States
AU: Lin, Y
EM: ylin@physics.auburn.edu
AF: Auburn University, Physics Department, Auburn, AL 36849, United States
AB: Entropy maps are constructed by mapping DMSP observations of diffuse auroral precipiation to the plasma sheet for quiescent IMF northward condition. These maps show a significant increase in entropy from the flank boundaries to the central plasma sheet. We further examine the entropy profiles for distinguishable hot and cold populations. Differences in entropy of hot particles seem to imply a heat flux from dawn to dusk, while differences in the cold population are related to transport and heating of the sheath population. We discuss these observations in the context of diffusive entry due to kinetic Alfven waves, Kelvin Helmholtz instability, and cusp reconnection. For active conditions, entropy maps are also constructed from a statistical ensemble of substorm events which are binned according to substorm growth, expansion, early-recovery, and late-recovery phases. We investigate the global profiles of total and specific entropy. We find a significant loss of total entropy in the near-earth plasma sheet in the transition between growth and expansion while changes in the specific entropy are less noticeable. Finally, we discuss changes in the global plasma profiles and entropy during substorms in the context of existing substorm models and consider what underlying physical processes could be responsible for the observed morphology.
UR: http://w3.pppl.gov/~jrj/magnetopause.html
DE: 2724 Magnetopause and boundary layers
DE: 2764 Plasma sheet
DE: 2784 Solar wind/magnetosphere interactions
DE: 7859 Transport processes
DE: 7867 Wave/particle interactions (2483, 6984)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting