Simulation of the Gas Filling and Evacuation Processes in an Inertial Confinement Fusion (ICF) Hohlraum

Abstract

In indirect inertial confinement fusion (ICF), the prediction of gas pressures and mass flow rates in the hohlraum is critical for fielding the hohlraum film and the support tent. To this end, it is desirable to understand the gas filling and evacuation process through the microcapillary fill tube and the support tent. In this work, a unified flow simulation of the filling and evacuation processes through the microcapillary fill tube and the support tent in an ICF hohlraum was conducted to study the gas pressure and mass flow rate in the hohlraum. The effects of the support tent size and the microcapillary fill tube size on the critical pressure variation and pressure difference across the hole on the support tent are examined. The results indicate that an increase in the diameter of the hole and the hole number leads to a smaller pressure difference across the hole on the support tent. If the diameter of the hole on the support tent is larger than 0.06 mm, the critical pressure variation rate is nearly independent of the diameter and the hole number. Increases in the diameter and decreases in the length of the microcapillary fill tube induce a larger critical pressure variation rate and pressure difference across the hole, which is conductive to fielding the hohlraum film.

Performance Analysis and Optimization of Sub-Atmospheric Purging through Microcapillaries in an ICF Cryogenic Target

“…Yu et al [36] studied the gas filling and leaking performance through unified flow theory, and proposed some methods to prevent ruptures of the sealing films. Wu et al [37] examined the pressure difference across the hole on the support tent during the microcapillary filling-evacuating process. They pointed out that increasing the hole diameter and decreasing the filling microcapillary length could induce a larger critical pressure variation and pressure difference across the hole.…”