Plasmoid Ejection by Alfvén Waves and the Fast Radio Bursts from SGR 1935+2154
Plasmoid Ejection by Alfvén Waves and the Fast Radio Bursts from SGR 1935+2154
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DOI：
10.3847/2041-8213/abafa8
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发表时间：
2020-06
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影响因子：
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通讯作者：
Yajie Yuan;A. Beloborodov;Alexander Y. Chen;Y. Levin
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文献类型：
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作者：
Yajie Yuan;A. Beloborodov;Alexander Y. Chen;Y. Levin
通过数值模拟，我们发现来自磁星地震的低振幅alfvsamn波传播到外层磁层，并转化为“等离子体”（闭合磁环），等离子体从恒星加速，将冲击波驱动到磁星风中。等离子体形成后很快就变成了一个薄薄的相对论煎饼。它将磁层磁力线推出，它们逐渐在煎饼后面重新连接，产生一种比磁星正常的自旋风强得多的可变风。在被放大的风中，重复的抛射驱动冲击波。我们认为这些喷射同时产生了从SGR 1935+2154探测到的x射线和射电爆发。磁层扰动的适度能量收支（约1040 erg）足以产生观测到的爆发。我们的模拟预测了一个来自磁层的狭窄（几毫秒）x射线尖峰，几乎与磁层外发射的射电暴同时到达。这种时间是由喷射物的极端相对论性运动引起的。
Using numerical simulations we show that low-amplitude Alfvén waves from a magnetar quake propagate to the outer magnetosphere and convert to “plasmoids” (closed magnetic loops) that accelerate from the star, driving blast waves into the magnetar wind. Quickly after its formation, the plasmoid becomes a thin relativistic pancake. It pushes out the magnetospheric field lines, and they gradually reconnect behind the pancake, generating a variable wind far stronger than the normal spindown wind of the magnetar. Repeating ejections drive blast waves in the amplified wind. We suggest that these ejections generate the simultaneous X-ray and radio bursts detected from SGR 1935+2154. A modest energy budget of the magnetospheric perturbation ∼1040 erg is sufficient to produce the observed bursts. Our simulation predicts a narrow (a few milliseconds) X-ray spike from the magnetosphere, arriving almost simultaneously with the radio burst emitted far outside the magnetosphere. This timing is caused by the extreme relativistic motion of the ejecta.