Measurement of Stimulated Raman Side-Scattering Predominance in Directly Driven Experiment
Abstract
Due to its particular geometry, stimulated Raman side-scattering (SRSS) drives scattered light emission at non-conventional directions, leading to scarce and complex experimental observations. Direct-irradiation campaigns at the SG-II UP facility have measured the scattered light driven by SRSS over a wide range of angles. It indicated an emission at large polar angles over a broad azimuthal range, sensitive to the plasma profile and laser polarization, resulting in a loss of about 5\% of the total laser energy. Direct comparison with back-scattering measurement has evidenced SRSS as the dominant Raman scattering process. The predominance of SRSS was confirmed by 2D particle-in-cell simulations, and its angular spread has been corroborated by ray-tracing simulations. The main implication is that a complete characterization of the SRS instability and an accurate measurement of the energy losses require the collection of the scattered light in a broad range of directions. Otherwise, spatially limited measurement could lead to an underestimation of the energetic importance of stimulated Raman scattering.
Keywords
Cite
@article{arxiv.2209.08251,
title = {Measurement of Stimulated Raman Side-Scattering Predominance in Directly Driven Experiment},
author = {Kevin Glize and Xu Zhao and Yihang Zhang and Changwang Lian and Shang Tan and Fuyuan Wu and Chengzhuo Xiao and Rui Yan and Zhe Zhang and Xiaohui Yuan and Jie Zhang},
journal= {arXiv preprint arXiv:2209.08251},
year = {2023}
}