LPI Mitigation Studies Via Laser Bandwidth at the Nike Laser Facility*

Increased laser bandwidth is currently of great interest as a means to mitigate laser plasma instabilities (LPI) in plasmas relevant to inertial confinement fusion. The output spectrum for the Nike laser (l_peak=248.5 nm) can be controlled by etalons in the front end over a range of (0.3-3 THz). This range is suitable for the investigation of bandwidth effects on slower growing instabilities such as stimulated Brillouin scattering (SBS) and cross-beam energy transport (CBET). A previous LPI campaign at Nike used a single type of low density foam target to produce large volume plasmas with estimated 5-10x longer density and velocity scale-lengths than solid CH targets. The current study explores SBS and CBET over a wider range of initial foam densities and utilizes exploding foil targets for comparison to LPI experiments from longer wavelength laser systems. Possible application of stimulated rotational Raman scattering (SRRS)[Weaver, et al. Applied Optics 2017] for broader bandwidth (> 3 THz) experiments will also be discussed.