Suppression of the Biermann Battery and Stabilization of the Thermomagnetic Instability in Laser Fusion Conditions
Suppression of the Biermann Battery and Stabilization of the Thermomagnetic Instability in Laser Fusion Conditions
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DOI：
10.1103/physrevlett.124.055001
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发表时间：
2020-02-03
影响因子：
8.6
通讯作者：
Bissell, J. J.
中科院分区：
文献类型：
--
作者：
Sherlock, M.;Bissell, J. J.
Biermann电池产生的磁场被认为是抑制激光-等离子体相互作用中热流的主要机制之一，并且由于热磁不稳定性，预计在某些情况下会呈指数增长[Tidman和Shanny，Phys. Fluids 17，1207（1974）]。然而，与这些预测相反，我们在一系列经典不稳定的激光聚变条件下进行了磁场动力学的弗拉索夫-福克-普朗克模拟，并发现场的产生被强烈抑制，防止运输磁化，稳定不稳定性。通过推导新的标度律，我们表明，这种稳定是一个后果（i）重抑制的Biermann电池在非局部条件下;（ii）快速对流的磁场的热流;和（iii）相对较短的字段长度尺度。我们的研究结果表明，经典模型大大高估了Biermann电池产生的磁场的重要性，以及激光聚变等离子体对热磁不稳定性的敏感性。
Magnetic field generated by the Biermann battery is thought to be one of the principal mechanisms behind the inhibition of heat flow in laser-plasma interactions, and is predicted to grow exponentially in some contexts due to the thermomagnetic instability [Tidman and Shanny, Phys. Fluids 17, 1207 (1974)]. In contrast to these predictions, however, we have conducted Vlasov-Fokker-Planck simulations of magnetic field dynamics under a range of classically unstable laser-fusion conditions, and find field generation to be strongly suppressed, preventing magnetization of the transport, and stabilizing instability. By deriving new scaling laws, we show that this stabilization is a consequence of (i) heavy suppression of the Biermann battery under nonlocal conditions; (ii) rapid convection of magnetic field by the heat flow; and (iii) comparatively short field length scales. Our results indicate that classical models substantially overestimate the importance of magnetic fields generated by the Biermann battery, and the susceptibility of laser-fusion plasmas to the thermomagnetic instability.