Dynamic Fluid-Kinetic (DyFK) simulation of density distributions along
high-latitude magnetospheric field lines as measured by IMAGE/RPI    

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

The IMAGE spacecraft experiment suite includes the Radio Plasma Imager (RPI)
which remotely sounds the large scale magnetospheric plasma environment through
transmission of coded swept frequency radio pulses, and reception of echoes. By
inversion of the measured echoes of transmitted signals from altitudes of
several RE in the high latitude magnetosphere, it has been possible to
determine extended distributions of density along these polar magnetic flux
tubes, frequently several such density profiles for different field lines for a
given IMAGE pass. In this presentation, we describe simulations of these
density profiles, including sequences of such profiles, using our Dynamic
Fluid-Kinetic (DyFK) model. The DyFK model couples a fluid, or moment-based,
treatment of the ionosphere in the 120-1100 km altitude range to a semi-kinetic
or hybrid (ions as particles) treatment for the transport above 1100 km to
several RE. The effects of ionospheric ionization and thermal electron heating
from soft auroral electron precipitation, transverse wave-driven ion heating
above the topside, and time-dependence and/or convection through regions or
periods of varying auroral processes are incorporated in these DyFK
simulations, and the simulated profiles compared to the observed density
profiles. 

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To be presented at the Western Pacific Geophysical Meeting, 
Wellington, New Zealand, 9-12 July 2002.