Direct auroral precipitation from the magnetotail during substorms

作者：Ashour-Abdalla, Maha^*; Schriver, David; El Alaoui, Mostafa; Richard, Robert; Walker, Raymond; Goldstein, Melvyn L.; Donovan, Eric; Zhou, Meng

来源：Geophysical Research Letters, 2013, 40(15): 3787-3792.

DOI：10.1002/grl.50635

• Acceleration
• Dipolarization
• Auroral
• magnetotail
• substorm

In this study, we examine the causes of electron precipitation during a substorm on 15 February 2008 that lead to auroral brightening. We use global kinetic simulations along with spacecraft and ground-based data. We find similar to keV electrons in the region modeled in the simulation precipitate into the premidnight sector at latitudes between 71 degrees and 75 degrees due to two distinct physical processes: (1) higher latitude precipitation due to electrons that undergo relatively rapid non-adiabatic pitch angle scattering into the loss cone just earthward of a reconnection region, and (2) lower latitude precipitation due to electrons that are more gradually accelerated primarily parallel to the geomagnetic field by Fermi acceleration. These latter electrons enter the loss cone much closer to Earth at similar to-15 to -10 R-E. The electron precipitation due to the combination of these two mechanisms coincides spatially with observed auroral brightening during the disturbed event.

• 出版日期2013-8-16
• 单位国家自然科学基金委员会; 南昌大学