Enhancing and optimizing laser-plasma instabilities as x-ray sources at NIF*

Experiment and simulation efforts are detailed that develop a high fluence, high photon energy continuum x-ray source by optimizing laser plasma instabilities on NIF. Such instabilities are typically minimized in fusion interactions to prevent drive-symmetry-breaking beam energy transfer and target preheat due to hot electron acceleration. Here instability mitigation efforts developed over previous decades are reversed to instead promote hot electron generation which leads to isotropic bremsstrahlung x-ray emission in a photon energy range that is otherwise inaccessible for high fluence materials effects testing. Experiments on Omega and NIF will be presented demonstrating selection of dominant laser plasma interactions via target and laser combinations, allowing control over both the x-ray spectral content and time of emission, as well as >10x increase in yield over typical setups and the most efficient 50 keV x-ray source to date on NIF.