Strong surface magnetic field generation in relativistic short pulse laser?plasma interaction with an applied seed magnetic field
Strong surface magnetic field generation in relativistic short pulse laser?plasma interaction with an applied seed magnetic field
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相对论短脉冲激光中强表面磁场的产生？等离子体与施加的种子磁场的相互作用
DOI：
10.1088/1367-2630/abc496
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发表时间：
2020
影响因子：
3.3
通讯作者：
Arefiev A V
中科院分区：
文献类型：
--
作者：
Weichman K;Robinson A P L;Murakami M;Arefiev A V
虽然等离子体通常表现为抗磁性，但我们证明了激光照射具有嵌入目标-横向种子磁场B种子的薄不透明目标可以触发在目标表面产生一个具有相反符号的数量级更强的磁场。当激光脉冲具有相对强度时，强表面场的产生是由激光加热电子的回旋旋转电流和冷电子的补偿电流引起的。我们推导了该表面场生成的预测尺度，B gen ~ - 2πB种子Δx/λ 0（在大光斑尺寸限制下），其中Δx为目标厚度，λ 0为激光波长，并进行了1D和2D细胞内粒子模拟，以证实其在广泛条件下的适用性。我们还证明了种子和表面产生的磁场都可以对应用相关的等离子体动力学产生强烈的影响，例如，在千特斯拉级别的种子磁场下，大大改变μm厚激光照射目标的整体膨胀和离子加速。
While plasma often behaves diamagnetically, we demonstrate that the laser irradiation of a thin opaque target with an embedded target-transverse seed magnetic field B seed can trigger the generation of an order-of-magnitude stronger magnetic field with opposite sign at the target surface. Strong surface field generation occurs when the laser pulse is relativistically intense and results from the currents associated with the cyclotron rotation of laser-heated electrons transiting through the target and the compensating current of cold electrons. We derive a predictive scaling for this surface field generation, B gen∼− 2πB seed Δx/λ 0 (in the large spot size limit), where Δx is the target thickness and λ 0 is the laser wavelength, and conduct 1D and 2D particle-in-cell simulations to confirm its applicability over a wide range of conditions. We additionally demonstrate that both the seed and surface-generated magnetic fields can have a strong impact on application-relevant plasma dynamics, for example substantially altering the overall expansion and ion acceleration from a μm-thick laser-irradiated target with a kilotesla-level seed magnetic field.