HR: 14:15h
AN: SM23D-02 INVITED     [Abstracts]
TI: Self-consistent Coupling Between Plasma and Fields in the Inner Magnetosphere
AU: * Zaharia, S
EM: szaharia@lanl.gov
AF: Los Alamos National Laboratory, MS D466, P.O. Box 1663, Los Alamos, NM 87545, United States
AU: Jordanova, V K
EM: vania@lanl.gov
AF: Los Alamos National Laboratory, MS D466, P.O. Box 1663, Los Alamos, NM 87545, United States
AU: Reeves, G D
EM: gdreeves@lanl.gov
AF: Los Alamos National Laboratory, MS D466, P.O. Box 1663, Los Alamos, NM 87545, United States
AU: Thomsen, M F
EM: mthomsen@lanl.gov
AF: Los Alamos National Laboratory, MS D466, P.O. Box 1663, Los Alamos, NM 87545, United States
AB: Observations show the magnetic field in the inner magnetosphere to be significantly distorted (depressed) during geomagnetic storms. While caused by the large amount of plasma injected in the inner magnetosphere, these distortions in turn strongly influence the evolution of particle populations in the near-Earth space. Therefore, in order to understand and model accurately the inner magnetosphere dynamics one needs to account self- consistently for the complex interaction between plasma and fields. To this end, we have developed a self- consistent inner magnetosphere code, obtained by iteratively coupling a kinetic ring current model with a 3-D plasma equilibrium code. In our approach, the magnetic field is computed in force balance with the kinetic model anisotropic pressures, and then fed back into the kinetic code. Here we report results obtained with our technique, improved to a full coupling of the two models (every 5 min.), and using magnetic boundary conditions from realistic empirical models such as T04S. Another new feature of our approach is the inclusion of the electric field induced by the time change of the self-consistent magnetic field, in a form greatly facilitated by the Euler potential representation of the latter. Using our improved self-consistent model, we simulate actual geomagnetic storms and we discuss the differences between the self-consistent results and those from kinetic model runs with a dipole field. We also assess during various storm phases the strength and location of magnetic field depressions, as well as of the induced electric field. Finally, we discuss how the distorted magnetic field differentially affects the energization of ring current particles at various pitch angles.
DE: 2730 Magnetosphere: inner
DE: 2740 Magnetospheric configuration and dynamics
DE: 2753 Numerical modeling
DE: 2778 Ring current
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly