Scaled impulse loading for liquid hydraulic response in IFE thick-liquid chamber experiments

Abstract

In an inertial fusion energy (IFE) target chamber using thick-liquid protection, placing liquid surfaces close to the fusion target helps to reduce pumping cost and final-focus stand-off distance. The impulse loading generated by the target on the adjacent jet surfaces provides the most important boundary condition for the subsequent liquid hydraulic response, pocket disruption, droplet generation, and pocket clearing and regeneration. However, liquid jets are difficult to use in current X-ray facilities that can simulate the X-ray ablation process. Instead, it is desirable to study liquid hydraulic response using water jets, employing scaled impulse loads delivered by chemical detonations or shock tubes. Because the pressure load generated by IFE targets is extremely short compared to the time required for significant liquid motion, only the time integrated impulse load is important to the liquid motion, not the detailed pressure history from ablation and venting. In this work, this impulse loading is determined using the 2-D gas dynamic code, TSUNAMI, and a comparison made between the impulse loads generated by IFE targets and by scaled chemical detonations.