The Formation of Electron Outflow Jets with Power-law Energy Distribution in Guide-field Magnetic Reconnection
The Formation of Electron Outflow Jets with Power-law Energy Distribution in Guide-field Magnetic Reconnection
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DOI：
10.3847/1538-4357/abcf29
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发表时间：
2021-02-01
影响因子：
4.9
通讯作者：
Crawford, C.
中科院分区：
文献类型：
--
作者：
Che, H.;Zank, G. P.;Crawford, C.
在观测上，具有幂律能谱的电子束通常与太阳耀斑有关。以往的研究发现，在磁场重联与引导场B-g大于0.1倍的渐近场B-0，电子束是无法发展，由于强烈的偏转所造成的引导场。使用粒子模拟的细胞，我们表明，在无力重联，电子开尔文-亥姆霍兹不稳定性的发展可以抑制霍尔效应，并产生长笛般的外流排气，其中电子和离子几乎冻结在磁场中。连续增长的电子速度剪切和E x B漂移的耦合驱动电子离开磁涡旋，并导致细长排气中具有幂律能谱的准直射流。电子喷流的空间密度与背景相当，且高度不均匀，这表明在引导场重联中存在不对称的密度结构。
Observationally, electron beams with power-law energy spectra are commonly associated with solar flares. Previous studies have found that during magnetic reconnection with a guide field B-g larger than 0.1 times the asymptotic field B-0, electron beams are unable to develop due to the strong deflection caused by the guide field. Using particle-in-cell simulations we show that in force-free reconnection, the development of an electron Kelvin-Helmholz instability can suppress the Hall effect and produce a flute-like outflow exhaust, in which both electrons and ions are nearly frozen-in with the magnetic field. The coupling of a continuously growing electron velocity shear and E x B drift drive the electrons out of magnetic vortices and results in collimated jets with a power-law energy spectrum in the elongated exhaust. The spatial density of electron jets is comparable to the background and is highly inhomogeneous, signifying on asymmetric density structure in guide field reconnection.