题目：Particle-in-Cell Simulations of Laser Channeling and Hosing in Fast Ignition
报告人：Prof.Chuang Ren （Laboratory for Laser Energetics ，University of Rochester，USA）
摘要：
A key issue for the fast ignition concept is to deposit the ignition pulse sufficiently close to the compressed fuel core to overcome the problem of divergence of laser-generated electrons. In one proposed scheme called ‘hole-boring,’ the ignition pulse pushes forward into the overdense plasma through its ponderomotive pressure. To avoid significant energy loss in the millimeter (mm) -long underdense plasma this scheme requires a channeling pulse to produce a low-density channel. We will present recent two-dimensional (2D) and three-dimensional (3D) particle-in-cell (PIC) simulation results for laser channeling in mm-scale underdense plasmas. The mm-scale 2D simulations show many new phenomena that were not present in previous 100 mm-scale experiments and simulations, including plasma buildup to above critical density in front of the laser, laser hosing/refraction, channel bifurcation and self-correction, and electron heating to relativistic temperatures. The channeling speed is much less than the linear group velocity of the laser. A scaling from the simulations shows, that low-intensity channeling pulses are preferred to minimize the required energy. Significant improvement of the transmission of the ignition pulse in a preformed channel has been demonstrated. The 3D PIC simulations show that the channeling speed is larger in 3D than in 2D due to stronger laser self-focusing. Laser hosing in both transverse planes simultaneously was also observed in these 3D PIC simulations for the first time.
Prof. Chuang Ren 简介：
Prof. Ren graduated from Tsinghua University with B.S. (1990) and M.S. (1993) in Physics. He received his Ph.D. in Physics from University of Wisconsin-Madision in 1998. He held postdoctoral and staff researcher positions at UCLA from 1999 to 2004. Currently, he is an Associate Professor in Department of Mechanical Engineering and a Scientist at Laboratory for Laser Energetics of University of Rochester.
时间：2010年7月16日（星期五）上午9：00
地点：中科院物理研究所B楼二段404会议室
联系人：李玉同 研究员 （Tel：82648014）
金奎娟 研究员 （Tel：82648099）
主办单位：中国科学院光物理重点实验室
