INNER MAGNETOSPHERIC MODELING WITH THE RICE CONVECTION MODEL FRANK TOFFOLETTO, STANISLAV SAZYKIN, ROBERT SPIRO and RICHARD WOLF Department of Physics and Astronomy, Rice University, Houston, TX 77005, U.S.A. Abstract. The Rice Convection Model (RCM) is an established physical model of the inner and middle magnetosphere that includes coupling to the ionosphere. It uses a many-fluid formalism to describe adiabatically drifting isotropic particle distributions in a self-consistently computed electric field and specified magnetic field. We review a long-standing effort at Rice University in magneto- spheric modeling with the Rice Convection Model. After briefly describing the basic assumptions and equations that make up the core of the RCM, we present a sampling of recent results using the model. We conclude with a brief description of ongoing and future improvements to the RCM. Key words: magnetosphere-inner, numerical modeling, plasma convection, ring current 1. Introduction Earth’s inner magnetosphere is home to an interesting variety of particle popula- tions and plasma processes. While radiation-belt particles (> 1 MeV energy) have been elegantly described by the adiabatic theory developed in the earliest days of the space age e.g., (Northrop, 1963), this picture can be disrupted by severe solar-wind disturbances (Li et al., 1993). The ring current, consisting mainly of ions and electrons in the 10–200 KeV energy range, carries a large fraction of the total particle energy of the magnetosphere and enough current to substantially affect the overall magnetic configuration. Coexisting in the same region of space as the radiation belt and ring current is the plasmasphere, consisting mainly of particles with energies < 1 eV. While the plasmasphere does not directly affect the magnetospheric magnetic field configuration, it still contains most of the mass of the magnetosphere. The plasmasphere exhibits a wide range of interesting plasma phenomena which affect wave propagation, particle loss, and heating processes in the ring current and radiation belt populations. Because many space-based assets are located in the inner magnetosphere and the underlying ionosphere, understanding the physical processes that control this region of space has important space weather implications. For example, the per- formance of geosynchronous communications spacecraft can be impaired by the effects of surface charging and the resultant arcing in solar panels. MeV outer- belt ‘killer electrons’ constitute another important space-weather hazard; they are Space Science Reviews 107: 175–196, 2003. © 2003 Kluwer Academic Publishers. Printed in the Netherlands.