Study of geospace storms based on a new observation-based model of the inner magnetosphere

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A new self-consistent and kinetic model for ring current particles in the inner magnetosphere is presented. A closed set of nonlinear time evolution equations is derived that incorporates kinetic particle dynamics and self-consistent development of the electromagnetic field. The particle transport is described by a five-dimensional collisionless drift kinetic equation, in which particle trajectories are approximated by their guiding centers under the influence of a time-dependent electromagnetic field. The time evolution of the electromagnetic field follows the Maxwell equations with the feedback from particles through electric currents. A numerical simulation code solving the system of equations in a global inner magnetosphere in three spatial dimensions(or five dimensions in phase space) is developed. It is demonstrated that the propagation of low-frequency plasma waves can successfully be described by the developed model. It is also found that the self-consistent coupling could affect the transport of energetic particles especially at low energies as well as the intensity and spatial distribution of field-aligned currents. These preliminary results suggest the importance of the self-consistent coupling in the global development of geomagnetic storms. Our approach extends the capability of modeling storm time phenomena occurring in the inner magnetosphere. These include sudden commencements(SCs), substorms, and ULF waves, and other associated phenomena.