摘要：Solar wind particles and ionospheric O ions influence the near-Earth plasma sheet and inner magnetospheric composition.We studied the behavior of H , O and He ions (9–210 keV) for intense and moderate geomagnetic storms of solar cycle 23 and 24.An average energy density of ions over a given interval and flux enhancement is estimated using observations from satellites at different L values, namely STICS sensor on-board Geotail spacecraft and HOPE spectrometer on-board Radiation Belt Storm Probes.It provides a comprehensive understanding of the energy density variation of H , O and He ions with the strength of IMF Bz, Psw, intensity of storms and L value.Statistically, we observed that (1) In the plasma sheet region, during main phase of the intense geomagnetic storm, < ε O /H and < ε He /H enhances, (2) < ε O /H is well correlated with Psw (CC = 0.86) and IMF Bz (CC = 0.85), (3) < ε O /H shows higher correlation (CC = 0.73) with Kp than < ε He /H (CC = 0.65), indicating a fairly good dependence on the strength of geomagnetic activity, (4) < ε O /H and < ε He /H dependence on L value indicates that O /H and He /H is more pronounced near L = 3.It is a cumulative extension of the previous studies on ion composition change which is in accordance with the existing picture of the plasma sheet and inner magnetosphere.
关键词：Inner magnetosphere; Plasma sheet; Ion composition; Energy density; Geomagnetic storm
