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Energetic oxygen: A direct coupling mechanism between the magnetosphere and thermosphere

Journal Article · · Geophys. Res. Lett.; (United States)
This study investigates the effects of the precipitation of energetic O/sup +/ ions (0.7--12 keV) into the atmosphere during magnetic storms. The energetic O/sup +/ ion flux produces a splash of lower energy neutral oxygen atoms at the top of the atmosphere. As a result of the photo-ionization and charge exchange with H/sup +/ ions in the plasmasphere, these backscattered atoms produce a low energy O/sup +/ flux that is more than 10 times larger in magnitude than the original energetic O/sup +/ flux. The energetic O/sup +/ events thus provide a potential source mechanism for the lower energy (< or approx. =30 eV) O/sup +/ ions observed in the plasmasphere. We also suggest that the energetic ion events may be self-sustaining in that some of the ionized 'splash' particles (< or approx. =10%) are subsequently accelerated by an as yet unidentified mechanism to the higher observed energies. We find that 96% of the incoming energy is transferred to the neutral atmosphere in the form of heating. Measured fluxes indicate heating rates as high as approx.0.4 ergs cm/sup -2/ sec/sup -1/ ster/sup -1/.
Research Organization:
Space Physics Research Laboratory, Department of Atmospheric and Oceanic Science, University of Michigan, Ann Arbor, Michigan 48109
OSTI ID:
5773245
Journal Information:
Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 6:9; ISSN GPRLA
Country of Publication:
United States
Language:
English