MHD Effects in Laser Heated Gases

New laser preheating techniques have substantially reduced laser plasma instabilities for MagLIF at SNL. These efforts have led to better agreement with the 3D HYDRA simulation code for stand-alone laser experiments, however they lack the applied magnetic field that is a key feature of MagLIF. In the interim, HYDRA is used, which features a full 3D MHD package including anisotropic thermal conduction, as well as the Nernst/Ettingshausen and Righi-Leduc terms. Results of 2D and 3D calculations are presented at the Z-Beamlet (2-4 kJ) and the NIF (single quad) scale (> 20 kJ). A key signature of magnetization during preheat, is higher electron temperature due to restriction of thermal conduction. With B_z the fuel is magnetized as it is heated, then quickly cools as a blast wave develops, limiting thermal conduction effects. Both 2D and 3D simulations show the potential for whole beam self-focusing and steering from thermal effects, that could lead to laser induced mix.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.