What effect do substorms have on the content of the radiation belts?
What effect do substorms have on the content of the radiation belts?
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DOI：
10.1002/2016ja022620
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发表时间：
2016-07
影响因子：
2.8
通讯作者：
Watt, C. E. J.
中科院分区：
文献类型：
--
作者：
Forsyth, C.;Rae, I. J.;Murphy, K. R.;Freeman, M. P.;Huang, C. -L.;Spence, H. E.;Boyd, A. J.;Coxon, J. C.;Jackman, C. M.;Kalmoni, N. M. E.;Watt, C. E. J.
亚暴是磁层中的基本动态过程，将捕获的太阳风磁能转换为等离子体能量。这些亚暴被认为是外辐射带高能电子增强的关键驱动力。亚暴将keV的“种子”粒子注入内磁层，随后通过波粒相互作用获得相对论能量;然而，亚暴直接或间接增强辐射带的程度以前从未被量化过。在这项研究中，我们研究增加和减少的总辐射带电子含量（TRBEC）以下亚暴和地磁平静的时间间隔。我们的研究结果表明，辐射带是固有的损耗，在亚暴和安静的时间间隔后的所有时间间隔在TRBEC的负中位数变化。然而，在亚暴间隔之后，TRBEC的增加高达3倍。亚暴或平静间隔与其对辐射带含量的最大影响之间存在1-3天的滞后，这表现在亚暴和平静间隔后TRBEC增加和减少的发生差异、亚暴或平静间隔后TRBEC的平均变化以及SuperMAG AL（SML）与TRBEC的交叉相关。然而，在长达6天的滞后期内，对TRBEC的增加和减少的发生有统计学意义的影响。辐射带含量的增加与SML和SYM-H有显著的相关性，但辐射带含量的减少与磁层活动水平没有明显的联系。辐射带具有固有的损耗亚暴使辐射带增加的可能性增加到50%辐射带对磁层活动的记忆长达6天
Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. Substorms inject a keV “seed” population into the inner magnetosphere which is subsequently energized through wave‐particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following substorms and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negative median change in TRBEC at all intervals following substorms and quiet intervals. However, there are up to 3 times as many increases in TRBEC following substorm intervals. There is a lag of 1–3 days between the substorm or quiet intervals and their greatest effect on radiation belt content, shown in the difference between the occurrence of increases and losses in TRBEC following substorms and quiet intervals, the mean change in TRBEC following substorms or quiet intervals, and the cross correlation between SuperMAG AL (SML) and TRBEC. However, there is a statistically significant effect on the occurrence of increases and decreases in TRBEC up to a lag of 6 days. Increases in radiation belt content show a significant correlation with SML and SYM‐H, but decreases in the radiation belt show no apparent link with magnetospheric activity levels. The radiation belts are inherently lossy Substorms increase the likelihood of an increase in the radiation belts to 50% The radiation belts have a memory of magnetospheric activity for up to 6 days