标题： 1D3V 粒子模拟研究相对论电子束在非均匀等离子体中的传播 显示英文标题

标题： 1D3V PIC simulation of propagation of relativistic electron beam in an inhomogeneous plasma

摘要： 最近的实验观察显示，通过对齐的碳纳米管阵列实现了兆安培级电子电流的有效传输 [Phys. Rev. Lett. 108, 235005 (2012)]。随后，这一结果基于不均匀等离子体中丝状不稳定性被抑制的理论进行了解释 [Phys. Plasmas 21, 012108 (2014)]。这种不均匀性是由于碳纳米管的电离而形成的。在本研究中，对相对论电子束（REB）通过不均匀背景等离子体的传播进行了完整的1D3V粒子-网格（PIC）模拟。展示了导致束发散的丝状不稳定性被抑制。模拟还证实，在非线性区域，当电子束通过横向密度不均匀的等离子体传播时，其传播效果更好。详细研究了不均匀性尺度长度、其幅度以及横向束温度等因素在抑制不稳定性中的作用。 显示英文摘要

摘要： A recent experimental observation has shown efficient transport of Mega Ampere of electron currents through aligned carbon nanotube arrays [Phys. Rev Letts. 108, 235005 (2012)]. The result was subsequently interpreted on the basis of suppression of the filamentation instability in an inhomogeneous plasma [Phys. Plasmas 21, 012108 (2014)]. This inhomogeneity forms as a result of the ionization of the carbon nanotubes. In the present work a full 1D3V Particle-in-Cell (PIC) simulations have been carried out for the propagation of relativistic electron beams (REB) through an inhomogeneous background plasma. The suppression of the filamentation instability, responsible for beam divergence, is shown. The simulation also confirms that in the nonlinear regime too the REB propagation is better when it propagates through a plasma whose density is inhomogeneous transverse to the beam. The role of inhomogeneity scale length, its amplitude and the transverse beam temperature etc., in the suppression of the instability is studied in detail.