The 6th International Conference on Matter and Radiation at Extremes (ICMRE2023)

213 / 2023-04-15 21:31:46

Time-dependent hohlraum radiation drive from the localized reemitted flux of gold spheres

radiation drive,hohlruam

Inertial Confinement Fusion Physics > Holraum and laser-plasma interaction-I

The hohlraum radiation drive on the capsule surface is a key physical quantity in indirect-drive inertial confinement fusion (ICF). However, it is difficult to decouple the hohlraum physics and the implosion physics, making it a great challenge to obtain the actual drive. To a) maintain the integrity of the hohlraum, b) avoid uncertainties introduced by the implosion, c) approach the real driving condition as closely as possible, and d) be suitable for long-pulse laser, we proposed to measure the localized reemitted flux of gold spheres at the center of the hohlraum to obtain the radiation drive.

By measuring the gold sphere localized reemission in both cylinder and I-shaped hohlraums, the time-dependent radiation drive on capsule was obtained. In experiment, the peak radiation drive inferred from the reemission flux of the gold spheres is about 12eV lower than that inferred from the 42-degree hohlraum leakage radiation flux. To verify this result, a View-Factor experiment was also conducted, in which one end of the hohlraum has a laser entrance hole (LEH) while the other end does not. The experimental results show that the radiation drive at the two ends differs by more than 10eV, which is consistent with the results inferred from the re-emission flux of gold spheres.

In summary, we have obtained the hohlraum radiation drive on capsule through the localized reemitted flux of gold spheres. Due to the nearly incompressibility of gold and the insensitivity of material parameters, this method can effectively avoid the complexity introduced by implosion physics and is also suitable for the long-pulse laser. It can provide experimental support for the design of new hohlraums and the study of hohlraum energetics.