Data Mining Reconstruction of Magnetotail Reconnection and Implications for Its First-Principle Modeling
Data Mining Reconstruction of Magnetotail Reconnection and Implications for Its First-Principle Modeling
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DOI：
10.3389/fphy.2021.644884
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
M. Sitnov;G. Stephens;T. Motoba;M. Swisdak
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文献类型：
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作者：
M. Sitnov;G. Stephens;T. Motoba;M. Swisdak
磁重联是在关键空间天气现象、太阳耀斑、日冕物质抛射和磁层亚暴中提供磁场拓扑变化、空间等离子体重新配置和能量释放的基本过程。由于其稀疏性，其多尺度性质很难通过观测来研究。在这里，我们展示了惰性学习方法（称为 K 最近邻）如何帮助挖掘历史空间磁力计记录中的数据，以提供地球磁尾重联的经验重建，其中太阳风-磁层相互作用的能量在亚暴期间储存和释放。数据挖掘揭示了两个具有不同属性的重新连接区域（X 线）。在中尾（距离地球约 30 RE，其中 RE 是地球半径）重连是稳定的，而靠近地球（约 20 RE）则是短暂的。研究发现，在磁尾电流片的动态粒子内细胞模拟中可以重现稳定和瞬态重连接过程的类似组合。
Magnetic reconnection is a fundamental process providing topological changes of the magnetic field, reconfiguration of space plasmas and release of energy in key space weather phenomena, solar flares, coronal mass ejections and magnetospheric substorms. Its multiscale nature is difficult to study in observations because of their sparsity. Here we show how the lazy learning method, known as K nearest neighbors, helps mine data in historical space magnetometer records to provide empirical reconstructions of reconnection in the Earth’s magnetotail where the energy of solar wind-magnetosphere interaction is stored and released during substorms. Data mining reveals two reconnection regions (X-lines) with different properties. In the mid tail ( ∼ 30 R E from Earth, where R E is the Earth’s radius) reconnection is steady, whereas closer to Earth ( ∼ 20 R E ) it is transient. It is found that a similar combination of the steady and transient reconnection processes can be reproduced in kinetic particle-in-cell simulations of the magnetotail current sheet.