Laser-plasma instabilities in ICF experiments on Laser MegaJoule and comparisons with simulations

Since the first fusion experiments performed in 2019[1], on the Laser MegaJoule (LMJ), the inertial confinement fusion (ICF) platform in the indirect drive configuration has been considerably extended. The LMJ facility is now capable of delivering up to 300kJ of UV energy on target using 80 beams evenly distributed among four rings, allowing for symmetric irradiation inside a hohlraum for the first time.

Over the past 3 years, several ICF experimental campaigns have been carried out to investigate implosion using low gaz-filled rugby shpaed, elliptical, and cylindrical gold hohlraums.

During these campaigns, laser plasma instabilities (LPI), mostly simulated Brillouin scattering and cross beam energy transfer, turn out to be major issues.

While presenting our improved modeling of LPI in hydro-radiative code with the purpose of taking into account spatial and temporal smoothing as well as perspectives for new models, the results of these campaigns will be discussed and compared to simulations. These results give us the opportunity to possibly improve our modeling strategy and help with the design of future campaigns on LMJ in the upcoming years.

[1] S. Liberatore, P. Gauthier, J. L. Willien, P. E. Masson-Laborde, F. Philippe et al. Phys. Plasmas 30, 122707 (2023)