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U.S. Department of Energy
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Auroral-zone plasma dynamics

Thesis/Dissertation ·
OSTI ID:5015552
Analysis of the USAF S3-3 charged particle data and electric field observations has provided extensive quantitative understanding of the auroral particle acceleration process. The results of an effort to use energetic charged particle observations to probe the altitude profile of auroral electric potential structures by applying adiabatic mapping theory are presented here. In situ energetic charged particle measurements differ from local electric field observations in that charged particles execute dynamic trajectories along the magnetic field lines and retain information on the spatial electric potential distribution in their velocity space distribution function. Although a unique determination of the potential distribution is not possible, basic differences between local or non-local acceleration are readily apparent in the particle observations. Together, the charged particle and electric field measurements have enabled us to form a reasonable picture of the auroral ''inverted-V'' structure which can then be applied to study the nonadiabatic processes that occur in these strong acceleration regions, such as energy scattering of ion and electron beams. Specifically, this study shows that a large scale auroral electric field exists at all times in the evening sector with an altitude distribution that is fairly unstructured at altitudes near and above one earth radius. Significant parallel potential drop is not observed below about 4000 kilometers altitude. At times, however, a substantial portion of the potential drop appears to lie in the low altitude region (4000-10,000 km).
Research Organization:
California Univ., Los Angeles (USA)
OSTI ID:
5015552
Country of Publication:
United States
Language:
English