Atmospheric Electron Spatial Range Extended by Thundercloud Electric Field Below the Relativistic Runaway Electron Avalanche Threshold
Atmospheric Electron Spatial Range Extended by Thundercloud Electric Field Below the Relativistic Runaway Electron Avalanche Threshold
复制标题
相对论失控电子雪崩阈值以下雷云电场扩展的大气电子空间范围
DOI：
10.1029/2021jd035958
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Enoto T.
中科院分区：
文献类型：
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作者：
Diniz G.;Wada Y.;Ohira Y.;Nakazawa K.;Enoto T.
宇宙射线阵雨一直在撞击大气层，其中包括高能电子。雷暴中的电场加速这些电子，这样它们就可以通过产生次级电子到达更远的距离。0.284 MV m−1以上的强场导致电子呈指数增长的相对论性失控电子雪崩（RREA）过程。即使电场较低，低于雷暴中通常测量的RREA阈值，电子动能的增加和二次电子的产生也可以在没有雪崩过程的情况下发生，称为宇宙射线阵雨的光谱修正（MOS）。这两种现象都与观测到的伽马射线辉光有关，这是雷暴中加速电子的轫致辐射。我们使用分析评估和Geant4蒙特卡罗模拟计算了RREA阈值以下电子的扩展范围和动能。例如，在略低于RREA阈值的0.280 MV m−1处，3 MeV电子通过零电场定义的连续减速近似（CSDA）范围获得了100%的原始动能，这与以往研究结果一致，是向RREA过程的过渡。即使在0.260 MV m−1的较低场下，该场的能量回收也允许注入的20 MeV电子束将其平均电子范围从零场配置中的73 m扩展到562 m。我们对初始电子能量为0.1-100 MeV，电场低于0.290 MV m−1的大气电子行为进行了分析计算和Geant4模拟。
Cosmic‐ray shower, hitting the atmosphere all the time, includes high‐energy electrons. Electric fields in thunderstorms accelerate these electrons so that they can reach farther distances with producing secondary electrons. The strong field above 0.284 MV m−1causes the Relativistic Runaway Electron Avalanches (RREA) process with an exponential increase of electrons. Even with lower electric fields below this RREA threshold which are usually measured in thunderstorms, an increase in electrons' kinetic energy and production of secondary electrons can occur without avalanche processes, known as Modification Of Spectra (MOS) of the cosmic‐ray shower. Both phenomena are related to observed gamma ray glow, which is bremsstrahlung emission from accelerated electrons in thunderstorms. We calculate an extended range and kinetic energy of electrons below the RREA threshold using an analytical evaluation and Geant4 Monte Carlo simulations. For example, at 0.280 MV m−1slightly below the RREA threshold, 3 MeV electrons gain 100% of their original kinetic energy through the passage of the continuous slowing down approximation (CSDA) range defined at the null electric field, which is consistent with results in previous studies as the transition to the RREA process. Even at a lower field of 0.260 MV m−1, the energy recovery by the field allows an injected 20 MeV electron beam to extend its average electron range from 73 m, in the null field configuration, to 562 m. We have performed analytical calculation and Geant4 simulations of atmospheric electron behavior for initial electron energy of 0.1–100 MeV and an electric field below 0.290 MV m−1.