HR: 0800h
AN: SM31B-0460 [Abstracts]
TI: Simulations of the formation of O+ trough zones in the polar cap ionosphere-magnetosphere coupling region
AU: * Jaafari, F B
EM: fbj7519@uta.edu
AF: Department of Physics, The University of Texas at Arlington, Arlington, TX 76019,
AU: Horwitz, J L
EM: horwitz@uta.edu
AF: Department of Physics, The University of Texas at Arlington, Arlington, TX 76019,
AU: Zeng, W
AF: Department of Physics, The University of Texas at Arlington, Arlington, TX 76019,
AB:
Thermal ion measurements by the Thermal Ion Dynamics Experiment(TIDE) on the POLAR spacecraft show that
the O+ densities in the polar cap near 6000 km altitude display structured variations featuring low-density
trough regions. We use the UT Arlington Dynamic Fluid-Kinetic (DyFK) model to model such O+ density
profiles. Treating different cases of TIDE observations near polar perigee by using available measured solar
wind parameters to drive a time-varying high-latitude convection model and incorporating auroral processes of
soft electron precipitation and wave-driven ion heating, we simulate the evolving high-latitude ionospheric plasma
transport and associated parameter profiles for several convecting flux tubes in the high-latitude ionosphere-
magnetosphere system, incorporating estimated locations of the auroral processes regions from HYDRA and the
Ovation auroral oval model. This auroral oval model has as inputs auroral precipitation measurements from
DSMP. For the convection patterns thus computed, these flux tubes nominally intersected the POLAR trajectory
where the density measurements were made. It is found that, owing chiefly to F-region recombination processes
during trajectory segments when the low altitude portions of such flux tubes in darkness, as well as incorporating
auroral fountain effects in the auroral region, normal and low trough-like densities at higher altitudes developed
along these flux tubes. The modeled densities near 6000 km altitudes will be compared with multiple trough
events featuring POLAR/TIDE-measured O+ densities for inside and outside of such trough regions.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2776 Polar cap phenomena
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting