HR: 1330h
AN: SM32A-1133    [PDF]
TI: Survey of Ion Beams Observed Near Substorm Onset by Polar/TIDE in the Nightside Magnetosphere
AU: * Christon, S P
EM: steve.christon@gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 692, Greenbelt, MD 20771 United States
AU: Moore, T E
EM: Thomas.moore@gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 692, Greenbelt, MD 20771 United States
AU: Chandler, M O
EM: michael.o.chandler@nasa.gov
AF: NASA Marshall Space Flight Center, Code SD50, Huntsville, AL 35812 United States
AU: Fok, M
EM: mei-ching.h.fok@gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 692, Greenbelt, MD 20771 United States
AU: Giles, B L
EM: barbara.giles@gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 692, Greenbelt, MD 20771 United States
AU: Liehmon, M W
EM: liemohn@umich.edu
AF: University of Michigan, Space Physics Research Laboratory, Ann Arbor, MI 48109 United States
AB: We investigate characteristics of ionospheric ion beams before, during, and after substorm onsets in the near-Earth ($\sim$6-9.6 Re) nightside magnetosphere using Polar spacecraft observations and minute resolution AE and Dst indices. The ionosphere continually supplies low energy ions to the plasma sheet. Ionospheric ion outflow increases strongly with increasing geomagnetic activity and ion transport from the ionosphere is predominantly as beams closely-aligned to the magnetic field. Polar's orbital apogee precession through low latitudes in 2001-2003 permits long-term insitu near-equatorial measurements by the Polar/TIDE $\sim$0.4-420 eV core plasma ion spectrometer. In a search for spatial and temporal patterns near substorm onset, detailed changes in ion flux anisotropy, average energy, and intensity level will be subject to qualitative and quantitative analysis. Historically, studies have provided average measurements and velocity moment analyses at low ion energies. This study will characterize the range of detailed low energy ionospheric ion flux variations at and around the time of substorm onset.
DE: 2451 Particle acceleration
DE: 2730 Magnetosphere--inner
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting