RADIATION TRANSPORT EFFECTS IN THE TARGET CHAMBER GAS OF THE LASER FUSION POWER-REACTOR SIRIUS-P

We present results from radiation-hydrodynamics calculations which sho w the central role resonant self-absorption plays in reducing radiativ e energy loss rates in high-gain ICF target chamber plasmas. Calculati ons were performed using a non-LTE radiative transfer model which we h ave recently coupled to our target chamber radiation-hydrodynamics cod e. The lower radiation fluxes escaping the plasma, which occur due to the self-absorption of line radiation in their optically thick cores, lead to significantly lower temperature increases at the surface of th e target chamber first wall. The calculations were performed for the S IRIUS-P laser-driven direct-drive ICF power reactor. In this conceptua l design study, high-gain targets release approximately 400 MJ of ener gy in the center of a gas-filled target chamber. The target debris ion s and x-rays are stopped in the gas, and the energy is reradiated to t he chamber mall over a much longer time scale. Because the time scales are comparable to the time it takes to thermally conduct energy away from the first surface, the thermal stresses and erosion rates for the first wall are greatly reduced.