Pump depletion and the Raman gap in ignition-scale plasmas

Laser-plasma instabilities under ignition conditions for direct-drive inertial confinement fusion are studied using two-dimensional particle-in-cell simulations with a combination of in-plane (PP) and out-of-the-plane (SP) lasers. The results show that stimulated Raman side-scattering can induce significant pump depletion and form a gap in the Raman scattered-light spectra that have been observed in experiments.