Particle fluxes at geosynchronous orbit and in the plasma sheet during a substorm: Implications for adiabatic convection

[摘要] Energetic particles are injected into the geosynchronous-orbit region of the Earth;;s magnetosphere during events called magnetospheric substorms. This injection process has been investigated utilizing the Magnetospheric Specification Model. Using time-dependent models of the magnetospheric electric and magnetic fields, we follow the ExB and gradient/curvature drifts of ions and electrons of differing energies within the modeling region. With allowance made for precipitation loss, the flux at each grid point is calculated from the initial and boundary condition fluxes. We used the data from the geomagnetic storm of March 22, 1979 to test the model;;s accuracy. Comparing predicted and observed geosynchronous particle fluxes, the model;;s predictions as to when the particles should arrive at various locations at the geosynchronous orbit are in good agreement with observations. However, assuming adiabatic drift of particles from the plasma sheet to the geosynchronous orbit region, with reasonable allowance for precipitation loss, the model obtains substorm fluxes that are about a factor of ten too high. This implies the existence of a powerful loss process that operates during a substorm on particles drifting between the middle plasma sheet and geosynchronous-orbit region.

[发布机构] Rice University

[效力级别] Physics