Demonstration of improved laser preheat with a cryogenically cooled magnetized liner inertial fusion platform

We report on progress implementing and testing cryogenically cooled platforms for Magnetized Liner Inertial Fusion (MagLIF) experiments. Two cryogenically cooled experimental platforms were developed: an integrated platform fielded on the Z pulsed power generator that combines magnetization, laser preheat, and pulsed-power-driven fuel compression and a laser-only platform in a separate chamber that enables measurements of the laser preheat energy using shadowgraphy measurements. The laser-only experiments suggest that similar to 89% +/- 10% of the incident energy is coupled to the fuel in cooled targets across the energy range tested, significantly higher than previous warm experiments that achieved at most 67% coupling and in line with simulation predictions. The laser preheat configuration was applied to a cryogenically cooled integrated experiment that used a novel cryostat configuration that cooled the MagLIF liner from both ends. The integrated experiment, z3576, coupled 2.32 +/- 0.25 kJ preheat energy to the fuel, the highest to-date, demonstrated excellent temperature control and nominal current delivery, and produced one of the highest pressure stagnations as determined by a Bayesian analysis of the data.

Automated summary

We present the progress made in implementing and testing cryogenically cooled platforms for MagLIF experiments. Two platforms were developed, one integrated on the Z pulsed power generator and one laser-only platform. The experiments showed that cooled targets achieved significantly higher energy coupling compared to warm experiments, with around 89% +/- 10% of incident energy coupled to the fuel. The integrated experiment, z3576, achieved the highest preheat energy coupling to date, demonstrating excellent temperature control and current delivery.