Mitigation of cross-beam energy transfer in inhomogeneous plasmas through increased laser bandwidth

We recently examined the efficacy of enhanced laser bandwidth for mitigation of cross-beam energy transfer (CBET) via a combination of linear theory and simulation^[1,2]. Our theoretical results demonstrated that, in the linear regime, bandwidth is effective at mitigating CBET for bandwidths exceeding the ion-acoustic wave (IAW) frequency. These results were verified by simulation, and we showed that nonlinear effects may lead to deviations from the linear scaling. However, these simulations were of homogeneous plasmas, whereas under direct laser-drive conditions the plasma includes significant density and velocity inhomogeneity. We now present results from an extended study in which we incorporate plasma inhomogeneity. We demonstrate that bandwidth remains effective at suppressing CBET in the linear regime, and show results from simulations investigating the impact of nonlinear effects.

[1] A. G. Seaton et al., “Theory and simulation of cross-beam energy transfer mitigation through increased laser bandwidth”, (Invited talk), 64th Annual Meeting of the APS DPP (2022).

[2] A. G. Seaton et al., Physics of Plasmas, 29(4), 042707 (2022).