Matter and Radiation at Extremes (Mar 2017)

First experimental comparisons of laser-plasma interactions between spherical and cylindrical hohlraums at SGIII laser facility

  • Yaohua Chen,
  • Zhichao Li,
  • Xufei Xie,
  • Chunyang Zheng,
  • Chuanlei Zhai,
  • Liang Hao,
  • Dong Yang,
  • Wenyi Huo,
  • Guoli Ren,
  • Jie Liu,
  • Xiaoshi Peng,
  • Tao Xu,
  • Yulong Li,
  • Sanwei Li,
  • Zhiwen Yang,
  • Liang Guo,
  • Lifei Hou,
  • Yonggang Liu,
  • Huiyue Wei,
  • Xiangming Liu,
  • Weiyi Cha,
  • Yukun Li,
  • Keli Deng,
  • Zheng Yuan,
  • Xiayu Zhan,
  • Haijun Zhang,
  • Baibin Jiang,
  • Wei Zhang,
  • Kai Du,
  • Xuewei Deng,
  • Yongkun Ding,
  • Xiaofeng Wei,
  • Wanguo Zheng,
  • Xiaodong Chen,
  • Xiantu He,
  • Ke Lan

DOI
https://doi.org/10.1016/j.mre.2017.01.001
Journal volume & issue
Vol. 2, no. 2
pp. 77 – 86

Abstract

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We present our recent laser-plasmas instability (LPI) comparison experiment at the SGIII laser facility between the spherical and cylindrical hohlraums. Three kinds of filling are considered: vacuum, gas-filling with or without a capsule inside. A spherical hohlraum of 3.6 mm in diameter, and a cylindrical hohlraum of 2.4 mm × 4.3 mm are used. The capsule diameter is 0.96 mm. A flat-top laser pulse with 3 ns duration and up to 92.73 kJ energy is used. The experiment has shown that the LPI level in the spherical hohlraum is close to that of the outer beam in the cylindrical hohlraum, while much lower than that of the inner beam. The experiment is further simulated by using our 2-dimensional radiation hydrodynamic code LARED-Integration, and the laser back-scattering fraction and the stimulated Raman scatter (SRS) spectrum are post-processed by the high efficiency code of laser interaction with plasmas HLIP. According to the simulation, the plasma waves are strongly damped and the SRS is mainly developed at the plasma conditions of electron density from 0.08 nc to 0.1 nc and electron temperature from 1.5 keV to 2.0 keV inside the hohlraums. However, obvious differences between the simulation and experiment are found, such as that the SRS back-scattering is underestimated, and the numerical SRS spectrum peaks at a larger wavelength and at a later time than the data. These differences indicate that the development of a 3D radiation hydrodynamic code, with more accurate physics models, is mandatory for spherical hohlraum study.