Magnetic-field generation and electron-collimation analysis for propagating fast electron beams in overdense plasmas.
Magnetic-field generation and electron-collimation analysis for propagating fast electron beams in overdense plasmas.
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DOI：
10.1103/physreve.83.036408
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发表时间：
2011-03
期刊：
影响因子：
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通讯作者：
H. Cai;Shaoping Zhu;Mo Chen;Siyu Wu;X. He;K. Mima
中科院分区：
文献类型：
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作者：
H. Cai;Shaoping Zhu;Mo Chen;Siyu Wu;X. He;K. Mima
本文提出了一种分析流体模型，用于超强激光脉冲与低密度核-高密度包层结构靶相互作用中产生的快电子束的人工准直。由于该理论清楚地预测了自发产生的磁场的特性及其对传输快电子的靶的等离子体参数的依赖性，因此它与快速点火的靶设计具有实质性的相关性。该理论还揭示了由密度跃变引起的背景电子横向（垂直于流速）流速的快速变化主导了这类靶的自发界面磁场的产生。研究发现，自发产生的磁场高达100 MG，这是足够大的准直过密等离子体中的快速电子输运。这个理论也支持使用二维粒子细胞代码进行的数值模拟。仿真结果与理论分析吻合较好。
An analytical fluid model is proposed for artificially collimating fast electron beams produced in the interaction of ultraintense laser pulses with specially engineered low-density-core-high-density-cladding structure targets. Since this theory clearly predicts the characteristics of the spontaneously generated magnetic field and its dependence on the plasma parameters of the targets transporting fast electrons, it is of substantial relevance to the target design for fast ignition. The theory also reveals that the rapid changing of the flow velocity of the background electrons in a transverse direction (perpendicular to the flow velocity) caused by the density jump dominates the generation of a spontaneous interface magnetic field for these kinds of targets. It is found that the spontaneously generated magnetic field reaches as high as 100 MG, which is large enough to collimate fast electron transport in overdense plasmas. This theory is also supported by numerical simulations performed using a two-dimensional particle-in-cell code. It is found that the simulation results agree well with the theoretical analysis.