First Experimental Comparisons of Laser-Plasma Interactions between Spherical and Cylindrical Hohlraums at SGIII Laser Facility

In thish report, we introduce our recent laser-plasmas instability (LPI) comparison experiment at the SGIII laser facility between the spherical hohlraums and the cylindrical hohlraums. Three kinds of filling are considered: vacuum, gas-filling with or without a capsule inside. 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 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 {\$}n\textunderscore c{\$} to 0.1 {\$}n\textunderscore c{\$} 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.