Formation of High-Density Field-Reversed Configurations on a Linear Transformer Driver

Brendan Sporer, University of Michigan

Photo of Brendan Sporer

Recent simulations by Slutz et al.1 have shown the potential for impressive fusion energy yield via compression of centimeter-scale field-reversed configurations (FRCs) using solid liners imploded by the Z-machine (20+ MA, 100 ns) at Sandia National Labs. A platform is being developed on the MAIZE linear transformer driver (1 MA, 200 ns) at the University of Michigan to study the formation and lifetime of high-density, high-field (10-30+ T) FRCs, which may someday prove suitable for compression at the Z facility. The proposed FRCs would be created at a very disparate physical and hydrodynamic scale than has previously been achieved2 to the authors’ knowledge. The ultimate goal of the platform is to explore the stability and lifetime scaling of such high-density FRCs for comparison with their lower-density cousins, and with the requirements for implosion on the Z-machine. In recent MAIZE experiments, visible fast-framing images combined with data from micro B-dot probes acting as an excluded flux array appear to indicate the presence of trapped bias flux (i.e. rudimentary FRCs) in the 9mm ID quartz discharge tubes. Upgrades to the bias field coils, excluded flux array, and imaging system are in progress, and should give further insight to, and control over, these regions of trapped bias flux. Simulation efforts are also in progress to better understand the Z-discharge pre-ionization phase preceding FRC formation. The hardware of the MAIZE FRC platform will be introduced, and the most recent experimental and computational results presented.

1Slutz, Stephen A., and Matthew R. Gomez. “Fusion gain from cylindrical liner-driven implosions of field reversed configurations.” Phys. Plasmas 28.4, 042707 (2021). 2 Alan L. Hoffman et al., “The Large-s Field-Reversed Configuration Experiment.” Fusion Technology 23:2, (1993).

This work was supported by the NNSA Laboratory Residency Graduate Fellowship program under DOE Contract No. DE-NA0003960, and by the NNSA Stewardship Sciences Academic Programs under DOE Cooperative Agreement DE-NA0003764. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.

Abstract Author(s): B.J. Sporer(1), A.P. Shah(1), G.V. Dowhan(1),T.J. Smith(1),S.A. Slutz(2), N.M. Jordan(1), and R.D. McBride(1), (1)University of Michigan, Ann Arbor, MI 48109 USA, (2)Sandia National Laboratories, Albuquerque, NM 87185 USA