本文利用Van Allen Probes卫星观测数据研究了2013年3月17日至18日强磁暴期间外辐射带高能电子通量(1.8-2.6 M e V)的演化。观测结果显示,在磁暴恢复期间,高能电子通量增涨约50-100倍。在L=4.1的附近,Van Allen Probes同步观测到高强度...本文利用Van Allen Probes卫星观测数据研究了2013年3月17日至18日强磁暴期间外辐射带高能电子通量(1.8-2.6 M e V)的演化。观测结果显示,在磁暴恢复期间,高能电子通量增涨约50-100倍。在L=4.1的附近,Van Allen Probes同步观测到高强度的合声波。本文基于高斯分布的哨声波谱密度分布和偶极子背景磁场模型,计算了弹跳平均电子共振扩散系数,并通过求解Fokker-Planck扩散方程对高能电子相空间密度的演化过程进行了估算。数值计算结果表明,观测到的合声波能够与辐射带高能电子产生回旋共振作用,有效地加速高能电子。本文的观测和模拟结果为合声波加速竞争机制引起的辐射带高能电子演化过程提供了一定依据。展开更多
Previous theoretical studies have shown that dayside chorus can produce butterfly distribution of energetic electrons in the Earth＇s radiation belts by preferentially accelerating medium pitch angle electrons, but th...Previous theoretical studies have shown that dayside chorus can produce butterfly distribution of energetic electrons in the Earth＇s radiation belts by preferentially accelerating medium pitch angle electrons, but this requires the further confirmation from high- resolution satellite observation. Here, we report correlated Van Allen Probes data on wave and particle during the 1 I-13 April, 2014 geomagnetic storm. We find that a butterfly pitch angle distribution of relativistic electrons is formed around the location L = 4.52, corresponding to the presence of enhanced dayside chorus. Using a Gaussian distribution fit to the observed chorus spectra, we calculate the bounce-averaged diffusion rates and solve two-dimensional Fokker-Planck equation. Numerical results demonstrate that acceleration by dayside chorus can yield the electron flux evolution both in the energy and butterfly pitch angle distribution comparable to the observation, providing a further evidence for the formation of butterfly distribution of relativistic electrons driven by very low frequency （VLF） plasma waves.展开更多
文摘本文利用Van Allen Probes卫星观测数据研究了2013年3月17日至18日强磁暴期间外辐射带高能电子通量(1.8-2.6 M e V)的演化。观测结果显示,在磁暴恢复期间,高能电子通量增涨约50-100倍。在L=4.1的附近,Van Allen Probes同步观测到高强度的合声波。本文基于高斯分布的哨声波谱密度分布和偶极子背景磁场模型,计算了弹跳平均电子共振扩散系数,并通过求解Fokker-Planck扩散方程对高能电子相空间密度的演化过程进行了估算。数值计算结果表明,观测到的合声波能够与辐射带高能电子产生回旋共振作用,有效地加速高能电子。本文的观测和模拟结果为合声波加速竞争机制引起的辐射带高能电子演化过程提供了一定依据。
基金supported by the National Natural Science Foundation of China(Grant Nos.41531072,41404130,41504125&41674166)
文摘Previous theoretical studies have shown that dayside chorus can produce butterfly distribution of energetic electrons in the Earth＇s radiation belts by preferentially accelerating medium pitch angle electrons, but this requires the further confirmation from high- resolution satellite observation. Here, we report correlated Van Allen Probes data on wave and particle during the 1 I-13 April, 2014 geomagnetic storm. We find that a butterfly pitch angle distribution of relativistic electrons is formed around the location L = 4.52, corresponding to the presence of enhanced dayside chorus. Using a Gaussian distribution fit to the observed chorus spectra, we calculate the bounce-averaged diffusion rates and solve two-dimensional Fokker-Planck equation. Numerical results demonstrate that acceleration by dayside chorus can yield the electron flux evolution both in the energy and butterfly pitch angle distribution comparable to the observation, providing a further evidence for the formation of butterfly distribution of relativistic electrons driven by very low frequency （VLF） plasma waves.
