High fluence x-ray source development via thermal and supra-thermal methods at the NIF

A high fluence source of hard x-rays (30+ keV) is desired for extreme radiation effects testing but it is challenging to boost yields in this energy range using existing laser-driven thermal effects (pumping atomic transitions in a heated plasma) or pulsed-power bremsstrahlung capabilities. Alternatives are being developed that adjust laser and target parameters to enhance the continuum emission of thermal sources or excite supra-thermal hot electrons via laser-plasma instabilities (LPI) that convert to bremsstrahlung x-ray emission in high-Z target walls. Work to control which LPI mechanism is dominant with target design and a comparison of continuum emissions on these sources will be presented along with other experimental data from campaigns and Omega and NIF.