HR: 1330h
AN: SM43B-01    [Abstracts]
TI: Remote Imaging of Storm-Phase Ion Heating
AU: * Zaniewski, A
EM: azaniewski@gmail.com
AF: West Virginia University, Dept. of Physics Hodges Hall, Morgantown, WV 26506
AU: Scime, E
EM: escime@wvu.edu
AF: West Virginia University, Dept. of Physics Hodges Hall, Morgantown, WV 26506
AU: Hairston, M
EM: hairston@utdallas.edu
AF: University of Texas, Dallas, William B. Hanson Center for Space Sciences,
AU: Thomsen, M
EM: mthomsen@lanl.gov
AF: Los Alamos National Lab, Space and Atmospheric Sciences, Los Alamos, NM
AU: Skoug, R
EM: rskoug@lanl.gov
AF: Los Alamos National Lab, Space and Atmospheric Sciences, Los Alamos, NM
AU: Henderson, M
AF: Los Alamos National Lab, Space and Atmospheric Sciences, Los Alamos, NM
AB: The MENA (Medium Energy Neutral Atom) instrument onboard the IMAGE spacecraft allows for global imaging of the magnetosphere in neutral atoms with energies ranging from 1 to 60 keV. Using known charge exchange cross sections and the properties of the instrument, the measured neutral atom energy spectra along each line-of-sight of the instrument can be converted into ion energy spectra. By fitting the ion energy spectra with a Maxwellian velocity distribution, global maps of the ion temperature during periods of elevated activity can be generated [Scime et al., 2002]. In this work, we combine remote ion temperature imaging using neutral atoms with an image processing algorithm that accounts for variations in the viewing geometry due to orbital precession and seasonal variations to sum images from eight large geomagnetic storms. Storm time images were separated into four intervals, pre-storm, main phase, early recovery, and late recovery. To distinguish between storms with differing convection electric field strengths, the storms were sorted by cross polar cap potential drops obtained from DMSP satellite measurements of ion flows. We find that storms with strong polar cap potential drops (i.e. < - 80 kV) exhibit more ion heating during the main phase and throughout the recovery than storms with more mild potential drops (i.e. ~ -50 kV). Ion heating clearly localized to the ring current region is also more apparent in those storms with stronger polar cap potential drops.
DE: 2716 Energetic particles, precipitating
DE: 2730 Magnetosphere--inner
DE: 2788 Storms and substorms
DE: 3394 Instruments and techniques
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly