How deeply do the energetic particles inject into the inner magnetosphere

Injections of energetic ions into the inner magnetosphere constitute one of the main sources of ring current enhancement during geomagnetic storm main phases, especially for energies in the range of 10~200keV. So far, the majority of investigations on energetic ion injections were performed at L>4.0 in the inner magnetosphere, while the study of ion injections in L<4.0 regions is relatively scarce. In this paper we have developed a method to identify ion injections for L<4.0 based on energetic ion fluxes vs L profiles during geomagnetic quiet times. We have selected 120 ion injections with 15 isolated injections and 105 storm-time injections based on the flux ratios between active and quiet periods. Energetic ions can be seldom injected into L<3.0 during isolated substorms, while they can reach much deeper orbits during storm-time. Additionally, we have calculated the correlation coefficients between the adjacent orbits during the geomagnetic active and quiet times in the same orbit categories. The results show that energetic ions with 150~750keV are hardly injected into L<4.0 for both ascending and descending periods. In contrast, lower energy ions with 50keV<E<150keV are injected into L<4.0 during geomagnetic storm-times, with deepest injection depth at L=2.4.