Analysis of the Effect of a High-$Z$-doped CH Ablator and Glass Ablators on Preheat and Hard X-Ray Radiation from Two-Plasmon Decay Electrons

The generation of preheating electrons from two-plasmon decay (TPD) can be mitigated by doping CH shells with Si or Ge or by using glass ablators. Simulations were carried out with a recent model for the source of the TPD fast electrons based on the results of warm-CH-shell implosions. The source energy varies as the threshold parameter $\sim I \quad \times \quad L$/$T_{e}$ at quarter critical. The presence of high-$Z$ dopants increases the temperature, which leads to a decrease in the energy deposited into the fast electrons and a reduction in the resulting preheat. The presence of high-$Z$ dopants, however, leads to higher radiation preheat. This presentation will discuss the effect of the dopants on the fast-electron source and the trade-off between the two forms of preheat in terms of the expected \textit{$\rho $R}'s for both warm-CH and cryogenic implosions. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.