Energy spectra of the major ion species in the ring current during geomagnetic storms

摘要: Using the University of Maryland/Max-Planck-Institut fur Aeronomie charge-energy-mass (CHEM) spectrometer on AMPTE Charge Composition Explorer (CCE) spacecraft, we have examined nearly equatorial storm time energy spectra four major magnetospheric ions, H+, O+, He+, and He++, over range 1–300 keV/e in L 3–6. The data were obtained during main early recovery phases all geomagnetic storms with minimum Dst less than −50 nT period September 1984 to November 1985. When are organized by local time, certain features emerge. In particular, there is a dip ions at 5–20 dawn-to-noon sector, while noon-to-dusk sector proton phase space density drops off sharply below ∼5 keV. We compared these those predicted model ion drift loss magnetosphere. calculates paths Volland-Stern electric field dipole magnetic determines losses due charge exchange strong pitch angle diffusion along paths. find that most consistent γ = 2 rotation nominal dawn-to-dusk eastward hours time. found be dominant process storm, producing qualitative agreement observed for species. There some quantitative disagreements, particularly prenoon which may explained either an additional or modified model.