科研之友
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摘要
There has been recent progress in understanding the sources and consequences of energetic O+ in the ring current and other regions of the magnetosphere. Various energization mechanisms that depend on geomagnetic activity, altitude, magnetic local time, and relative position within the auroral oval acting on O+ have been proposed. Our understanding of the altitude and magnetic local time variation of these processes has not proceeded as rapidly, however. Contemporary magnetosphere models now include species-dependent dynamics. These models will benefit from improved spatial and altitudinal knowledge of O+ energization processes. Here we present a global view of O+ upward flows observed at DMSP (850 km) compared to outflow rates observed by Polar (5000-7000 km) during nonstorm times in the framework of dynamic auroral boundary coordinates. This study considers observational proxies for heating and energization mechanisms and shows that these proxies set useful boundaries on their efficacy. This study indicates that during nonstorm times (1) energization between 850 km and 5000-7000 km is predominantly transverse, (2) the efficiency of ion energization is often not focused at the boundaries of the auroral zone, and (3) auroral zone acceleration above DMSP is relatively more important in the cusp than at midnight.
- 出版日期2012-4-17
