Stability Analysis of Dynamic Screw-Pinch Driven Thin-Foil Liner Implosions

The dynamic screw pinch (DSP) has been shown to reduce instability growth in metal liner implosions relevant to magnetized liner inertial fusion (MagLIF) [1]. To experimentally investigate the effects and potential limits of instability mitigation in DSP implosions, a suite of return-current structures was designed and tested on the MAIZE facility at the University of Michigan. The suite allows a large range of initial drive field ratios to be tested, with initial axial to azimuthal magnetic field ratios of ~0.3 to >1.0, while minimally impacting the load inductance of the system. This was accomplished using various pitch angles, radii, and number of intertwined helices in the return-current structures. The experiments were performed using 400-nm-thick metal foil liners. The implosion dynamics were captured using a 12-frame optical self-emission camera. Results from this study will be presented, along with considerations for future experiments.

[1] P. C. Campbell et al., PRL 125, 035001 (2020)