Modeling Ring Current and Radiation Belt Dynamics During October 2001

V.K. Jordanova (University of New Hampshire, Durham, NH 03824), Y. Miyoshi,
M.F. Thomsen, J.F. Fennell, G.D. Reeves, D.S. Evans, P.C:son Brandt, and 
S. Ohtani

We study the dynamical coupling of the ring current and the radiation belts
during the major storm of October 21, 2001, with minimum Dst=-166 nT and
maximum Kp=8- at ~22 UT. This storm had a rapid main phase, followed by a
period of strong geomagnetic activity lasting for more than a day, and a slow
storm recovery. We use our global physics-based model, which solves the
kinetic equation for H+, O+, and He+ ions and electrons. Time-dependent
plasma inflow from the magnetotail, convective transport, and losses due to
collisions, dayside outflow, and wave-particle interactions are included. We
extend our model to relativistic energies and add in radial diffusion. Model
results are compared with in-situ data from NOAA and Polar, and global images
from IMAGE spacecraft. We demonstrate the dominant role of magnetospheric
convection for the injection of ring current particles at energies E<80 keV
and the formation of the asymmetric ring current. The transport of
high-energy (E>80 keV) particles is dominated by radial diffusion.  Strong
EMIC waves are excited near minimum Dst and during the recovery phase of the
storm. Pitch angle scattering by these waves caused significant particle
precipitation into the atmosphere and about 15-30% recovery of the Dst index.
The characteristics of this ion precipitation as a plausible mechanism for
generation of detached proton auroral arcs discovered by the IMAGE satellite
are investigated.

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Presentation at the Yosemite Conference of Inner Magnetospheric Interactions,
3 - 6 February 2004, Yosemite, California, USA