Ar and Kr on deuterium gas-puff staged Z-pinch implosions on a 1-MA driver: Experiment and simulation

Abstract

Recent experiments on the 1 MA, 100 ns Zebra driver at the Nevada Terawatt Facility at the University of Nevada, Reno, investigated the compression of a deuterium target by a high-atomic-number (Ar or Kr) gas-puff liner. Pinch stability improved with axial premagnetization of 1–2 kG observed as a decrease in magneto-Rayleigh-Taylor instability growth. Implosion dynamics and stagnation conditions were studied computationally with the radiation-MHD code MACH2 using initial conditions that approximate those in the experiment. Typical average and peak implosion velocities exceeded 300 and 400 km/s, respectively, which raised the target adiabat by shock heating as the front converges on axis, at which time the target is adiabatically compressed to stagnation. Experimental fusion yields of up to 2 × 109 for Ar liner on D target implosions were measured, while with a Kr liner yields up to 1 × 1010 were measured. Higher yields in Kr compared to Ar were also calculated in 2-D MACH2 simulations. These observations will be further tested with other radiation-MHD codes, and experiments on the 1 MA LTD-III machine at UC San Diego.

What are the fastest routes to fusion energy?

“…1) Our results are only 30% lower than the best achieved by government-funded efforts with orders of magnitude less resources expended. Only two other private fusion efforts, MIFTI 27 and TAE, 28 have reported fusion yields, and only LPPFusion and TAE have done so with their own equipment. The MIFTI results were obtained on the publicly funded Zebra z-pinch at the University of Nevada.…”

An overview of magneto-inertial fusion on the Z machine at Sandia National Laboratories

“…This proofof-concept has played an important role in motivating the ARPA-E ALPHA fusion program focused on advancing MIFrelevant, intermediate-density fusion approaches (i.e. between ICF and MCF) with a direct emphasis on lower-cost pathways to commercially viable fusion energy [117][118][119][120]. While MagLIF research at Sandia National Laboratories is primarily funded by the United States Inertial Confinement Fusion program and mainly interested in generating single shot, multi-MJ fusion yields for the Stockpile Stewardship Program [121], the possibility of high gain is encouraging from a fusion energy perspective [16].…”

TWELVE AXIOMS OF FUSION ENERGY R&D

“…However, all had predicted in 2012 to 2014 that they would implement commerclal fusion power by dates ranging from 2018 to 2024. LPP [4] and MIFTI [5] appear to be unique among the privately funded so-called fusion energy companies in actually producing a significant number of fusion neutrons, but LPP's predictions for commercialization have suffered the same trajectory as its rivals. LPP has pursued the dense plasma focus (DPF) which was a leading neutron producer back in the 1960's and 1970's, but no DPF project has been able to increase neutrons per pulse beyond 1E12 (D-D), a level achieved more than 40 years ago [6].…”