HYDRA Simulations of the Effect of External Magnetic Fields on Plasma Temperature and X-Ray Emission in Titanium-Doped Foam Targets*

The application of external magnetic fields to laser driven targets reduces electron thermal transport which can increase electron temperatures and improve high energy photon emission, particularly for multi-keV photons.  Simulations and experiments report up to 50% increases in the electron temperature in magnetized targets, consistent with unrestrained thermal transport along the external field lines.  However, the strength and orientation of the magnetic field can vary significantly over the laser pulse due to MHD effects including the Nernst effect and the Biermann battery, which are often neglected in the literature.  The simulations presented here use the radiation-hydrodynamics code HYDRA to predict high-energy X-ray emission, electron temperatures, and magnetic field evolution in Titanium doped cylindrical foam targets at 3mg/cm^3 with a direct laser drive in external magnetic fields ranging from 0 to 100 Tesla.  The simulations investigate the influence of the Nernst effect and Biermann battery on electron temperatures and X-ray emission, and the results are compared with experiments performed with the Janus laser.