Injection of solar wind and ionospheric ions into the inner magnetosphere during storm-time substorms

The October 28, 2001 geomagnetic storm (minimum Dst ~-157 nT) was characterized by a number of substorms, most notably at the peak of the main phase, at ~1200 UT. We have investigated ion access to the plasma sheet and inner magnetosphere during this storm by using the large-scale kinetic (LSK) particle tracing technique and ion sources in the solar wind and in the ionosphere. The three-dimensional, time- dependent magnetic and electric fields for this calculation were obtained from a global magnetohydrodynamic (MHD) simulation that used solar wind and interplanetary magnetic field data from the GEOTAIL spacecraft. To study solar wind entry, we launched ions upstream of the bowshock beginning two hours prior to the shock arrival and continuing for twelve hours during the sudden storm commencement and the main phase of the storm, as well as the substorm that occurred at ~1200 UT. Ions were launched with the solar wind streaming velocity and thermal speed measured at that time. The outflow rates and locations of ionospheric H+ and O+ ions were specified by empirical models. H+ and O+ densities in the near-Earth plasma sheet obtained from the LSK calculations were compared with densities obtained by inverting IMAGE/HENA data, with special emphasis on the effect of the substorm on ion distributions in the inner magnetosphere.