A Statistical Survey of Radiation Belt Dropouts Observed by Van Allen Probes

作者：Xiang, Zheng; Tu, Weichao^*; Ni, Binbin^*; Henderson, M. G.; Cao, Xing

来源：Geophysical Research Letters, 2018, 45(16): 8035-8043.

DOI：10.1029/2018GL078907

• radiation belt dropout
• wave particle interaction
• EMIC wave
• phase space density
• magnetopause shadowing
• radial diffusion

A statistical analysis on the radiation belt dropouts is performed based on 4 years of electron phase space density data from the Van Allen Probes. The mu, K, and L* dependence of dropouts and their driving mechanisms and geomagnetic and solar wind conditions are investigated using electron phase space density data sets for the first time. Our results suggest that electronmagnetic ion cyclotron (EMIC) wave scattering is the dominant dropout mechanism at low L* region, which requires the most active geomagnetic and solar wind conditions. In contrast, dropouts at high L* have a higher occurrence and are due to a combination of EMIC wave scattering and outward radial diffusion associated with magnetopause shadowing. In addition, outward radial diffusion at high L* is found to cause larger dropouts than EMIC wave scattering and is accompanied with active geomagnetic and solar wind drivers.

• 出版日期2018-8-28
• 单位Los Alamos; 武汉大学