Arnold H, Drake J F, Swisdak M, Guo F, Dahlin J T, Chen B, Fleishman G, Glesener L, Kontar E, Phan T, Shen C
IREAP, University of Maryland, College Park, Maryland 20742-3511, USA.
Los Alamos National Lab, Los Alamos, New Mexico 87545, USA.
Phys Rev Lett. 2021 Apr 2;126(13):135101. doi: 10.1103/PhysRevLett.126.135101.
The first self-consistent simulations of electron acceleration during magnetic reconnection in a macroscale system are presented. Consistent with solar flare observations, the spectra of energetic electrons take the form of power laws that extend more than two decades in energy. The drive mechanism for these nonthermal electrons is Fermi reflection in growing and merging magnetic flux ropes. A strong guide field suppresses the production of nonthermal electrons by weakening the Fermi drive mechanism. For a weak guide field the total energy content of nonthermal electrons dominates that of the hot thermal electrons even though their number density remains small. Our results are benchmarked with the hard x-ray, radio, and extreme ultraviolet observations of the X8.2-class solar flare on September 10, 2017.
首次展示了在宏观系统中磁重联期间电子加速的自洽模拟。与太阳耀斑观测结果一致，高能电子的能谱呈幂律形式，能量范围延伸超过两个数量级。这些非热电子的驱动机制是在不断增长和合并的磁通量绳中的费米反射。强引导场通过削弱费米驱动机制来抑制非热电子的产生。对于弱引导场，尽管非热电子的数密度仍然很小，但其总能量含量却主导着热电子的总能量含量。我们的结果与2017年9月10日X8.2级太阳耀斑的硬X射线、射电和极紫外观测结果进行了对比。
