Dynamic Fluid-Kinetic Simulations on High Plasma Densities at Polar
Latitudes Observed by IMAGE RPI during Magnetic Storms

Tu, J,  Horwitz, J L,  Fung, S F,  Reinisch, B W

We simulate the unusually high plasma density profiles observed by the
Radio Plasma Imager (RPI) on board the IMAGE satellite over the polar
ionosphere during November 6 2000 geomagnetic storm, using our Dynamic
Fluid semi-Kinetic (DyFK) ionospheric transport model. [Image] RPI
[Image] can remotely probe the surrounding plasma environment up to
several R$_{E}$ away from the IMAGE spacecraft by broadcasting a sweep
of radio wave signals from 3 kHz to 3MHz. The polar cap electron
density profiles are obtained from an inversion of guided echoes
received back at the [Image] RPI [Image] instrument at high latitudes.
The DyFK model couples a moment-based fluid model for altitudes from
120 - 1100 km to a generalized semi-kinetic treatment for the topside
through 4 R$_{E}$ region. Various processes, such as cleft/auroral
soft electron precipitation, transverse ion heating by broadband ELF
waves, and hot plasma-driven potential drops are incorporated into the
generalized semi-kinetic treatment of topside ionosphere. Simulation
results are in fgood agreement with those observed. Based on the
comparison between the simulation and observation, we discuss the
mechanisms that can produce such high plasma densities over the polar
ionosphere during magnetic storms.