Quantitative Evaluation of Radial Diffusion and Local Acceleration Processes During GEM Challenge Events
Quantitative Evaluation of Radial Diffusion and Local Acceleration Processes During GEM Challenge Events
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DOI：
10.1002/2017ja025114
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发表时间：
2018-03
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通讯作者：
Qianli Ma;Wen Li;J. Bortnik;R. Thorne;Xiangning Chu;L. Ozeke;Geoff D. Reeves;Craig A. Kletzing;W. Kurth;G. Hospodarsky;Mark J. Engebretson;H. Spence;D. N. Baker;J. B. Blake;J. F. Fennell;S. Claudepierre
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作者：
Qianli Ma;Wen Li;J. Bortnik;R. Thorne;Xiangning Chu;L. Ozeke;Geoff D. Reeves;Craig A. Kletzing;W. Kurth;G. Hospodarsky;Mark J. Engebretson;H. Spence;D. N. Baker;J. B. Blake;J. F. Fennell;S. Claudepierre
我们模拟的辐射带电子通量的增强在选定的地球空间环境建模（GEM）的挑战事件，定量比较在不同条件下的相对论电子加速的主要过程。货车艾伦探测器在2013年3月17日至18日的风暴期间和2013年9月19日至20日的非风暴期间都观测到了显著的电子通量增强，但这两次事件的等离子体波和高能电子的分布有很大的不同。在2013年3月17日至18日，SYM-H的最小值达到-130 nT，强烈的合唱波（峰值Bw ~140 pT）出现在3.5 5.5处，能量高达3 MeV的电子通量在L > 5.5时增加了约5倍。这两个电子通量增强事件的模拟使用现有的波分布和扩散系数从GEM焦点小组辐射带建模的定量评估。通过比较局部电子加热和径向传输的各自作用，我们的模拟表明，与合唱波的共振相互作用是占主导地位的过程，特别是在风暴时间事件期间的电子通量增强，特别是在通量峰值位置附近，而超低频波的径向扩散在非风暴时间事件期间的增强中起着主导作用。合并这两个过程合理地再现所观察到的电子通量增强的位置和幅度。
We simulate the radiation belt electron flux enhancements during selected Geospace Environment Modeling (GEM) challenge events to quantitatively compare the major processes involved in relativistic electron acceleration under different conditions. Van Allen Probes observed significant electron flux enhancement during both the storm time of 17–18 March 2013 and non–storm time of 19–20 September 2013, but the distributions of plasma waves and energetic electrons for the two events were dramatically different. During 17–18 March 2013, the SYM‐H minimum reached −130 nT, intense chorus waves (peak Bw ~140 pT) occurred at 3.5 5.5, and electron fluxes at energies up to 3 MeV increased by a factor of ~5 at L > 5.5. The two electron flux enhancement events were simulated using the available wave distribution and diffusion coefficients from the GEM focus group Quantitative Assessment of Radiation Belt Modeling. By comparing the individual roles of local electron heating and radial transport, our simulation indicates that resonant interaction with chorus waves is the dominant process that accounts for the electron flux enhancement during the storm time event particularly near the flux peak locations, while radial diffusion by ultralow‐frequency waves plays a dominant role in the enhancement during the non–storm time event. Incorporation of both processes reasonably reproduces the observed location and magnitude of electron flux enhancement.