Impact of laser bandwidth on SRS in ICF plasmas

In laser driven ICF plasmas, higher pressures are used to drive more hydrodynamically stable implosions, but the pressure (intensity) is limited by laser plasma instabilities (LPI) like stimulated Raman scattering (SRS). Bandwidth is known to stabilize or mitigate LPIs particularly when it is comparable to or greater than the growth-time of the instability¹. Because of their faster growth rate, plasmon-based instabilities like SRS need more bandwidth for suppression than ion-acoustic instabilities like SBS or filamentation. However, relatively large bandwidths (Δν > 2 THz) can be impressed on an otherwise narrow-bandwidth laser using stimulated rotatational Raman scattering (SRRS) in gas². Here we use the LPSE³ code to investigate the impact of SRRS-generated bandwidths on SRS in laser-driven plasmas and report on the results.

1. J.J. Thomson, Nucl.Fusion 15, 237 (1975); S.P. Obenschain and N.C. Luhmann, Appl.Phys.Lett. 30, 452 (1977).

2. J.L. Weaver, et al., Appl.Opt. 56, 8618 (2017).

3. A.V. Maximov et. al, BAPS 62, 75 (2017); J.W. Bates et al., Phys Rev. E 97, 061202 (2018)