Thermal Analysis of Candidate Armor Materials for Use in the Magnetic Cusp Field HAPL Reactor Design

The introduction of magnetic cusp fields into the High Average Power Laser (HAPL) reactor design is to prevent target ions from interacting with the armor layer. Diverting the ions and preventing their impact on the chamber armor eases thermal design constraints considerably. The BUCKY code was used to simulate thermal loads for the candidate armor materials tungsten and silicon carbide.

Parametric analysis was done to ascertain the peak temperature rise in the armor due to X-rays from the HAPL target thermonuclear ignition. Temperature values as a function of chamber armor radius were obtained using initial conditions of T₀ = 600 °C and xenon buffer gas pressures of 66.7, 666.7 and 6666.1 mPa (0.5, 5 and 50 mTorr). The armor radius was decreased until thermal thresholds were met (2400 °C and 1000 °C for tungsten and silicon carbide, respectively) to determine the minimum allowable radius of the HAPL chamber.

A second set of parametric simulations were performed at xenon gas initial pressures of 666.7 and 6666.1 mPa (5 and 50 mTorr) and temperature of 600°C to a time of 5 ms to observe the effect of re-radiation from the buffer gas on the surface temperature of tungsten and silicon carbide.