Generation of scaled protogalactic seed magnetic fields in laser-produced shock waves
Generation of scaled protogalactic seed magnetic fields in laser-produced shock waves
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DOI：
10.1038/nature10747
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发表时间：
2012-01-26
期刊：
影响因子：
64.8
通讯作者：
Miniati, F.
中科院分区：
文献类型：
--
作者：
Gregori, G.;Ravasio, A.;Miniati, F.
银河系磁场起源的标准模型是通过发电机或湍流过程将种子场放大到与目前观测一致的水平（1-3）。虽然其他机制也可能起作用（4，5），但在没有原始场的情况下，来自失调压力和温度梯度的电流（比尔曼电池过程）不可避免地伴随着星系的形成。在原星系结构坍缩引起的激波几何不对称性的驱动下（6），比尔曼电池被认为能产生大约10（-21）高斯的微小种子场（参考文献7，8）。在过去的二十年里，随着高功率激光系统的出现，开辟了一个新的研究领域，其中，使用简单的比例关系（9，10），天体物理环境可以有效地在实验室中再现（11，12）。在这里，我们报告的实验结果，产生种子磁场的比尔曼电池效应。我们表明，这些结果可以扩展到星系际介质，在那里，湍流，作用于约7亿年的时间尺度，可以放大种子场（13，14）足以影响星系的演化。
The standard model for the origin of galactic magnetic fields is through the amplification of seed fields via dynamo or turbulent processes to the level consistent with present observations(1-3). Although other mechanisms may also operate(4,5), currents from misaligned pressure and temperature gradients (the Biermann battery process) inevitably accompany the formation of galaxies in the absence of a primordial field. Driven by geometrical asymmetries in shocks(6) associated with the collapse of protogalactic structures, the Biermann battery is believed to generate tiny seed fields to a level of about 10(-21) gauss (refs 7, 8). With the advent of high-power laser systems in the past two decades, a new area of research has opened in which, using simple scaling relations(9,10), astrophysical environments can effectively be reproduced in the laboratory(11,12). Here we report the results of an experiment that produced seed magnetic fields by the Biermann battery effect. We show that these results can be scaled to the intergalactic medium, where turbulence, acting on timescales of around 700 million years, can amplify the seed fields(13,14) sufficiently to affect galaxy evolution.