  Backward stimulated Raman scattering is a three-wave coupling instability
requiring the matching of an incoming pump light wave to a scattered light wave
and electron plasma wave. It can be harmful to laser-driven inertial
confinement fusion because of the reflection of a part of incident laser flux
and the generation of suprathermal electrons that preheat the fuel. It is
believed that by increasing the laser bandwidth one can suppress the excitation
of Raman scattering and mitigate its detrimental effects. It is demonstrated in
this paper that using a broad bandwidth laser has little effect on stimulated
Raman scattering in the kinetic inflation regime where Landau damping
dominates, as the additional bandwidth allows the electron plasma wave to match
a wider range of laser frequencies. As a result, plasma wave saturation and
Raman backscattering levels remain high even when the laser bandwidth is much
larger than the effective instability growth rate.
