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arXiv · 1610.09092

Seeding the m = 0 instability in dense plasma focus Z-pinches with a hollow anode

J. X. Liu·J. Sears·M. McMahon·K. Tummel·C. Cooper·D. Higginson·B. Shaw·A. Povilus·A. Link·A. Schmidt
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Abstract

The dense plasma focus (DPF) is a classic Z-pinch plasma device that has been studied for decades as a radiation source. The formation of the m = 0 plasma instability during the compression phase is linked to the generation of high-energy charged particle beams, which, when operated in deuterium, lead to beam-target fusion reactions and the generation of neutron yield. In this paper, we present a technique of seeding the m = 0 instability by employing a hollow in the anode. As the plasma sheath moves along the anode's hollow structure, a low density perturbation is formed and this creates a non-uniform plasma column which is highly unstable. Dynamics of the low density perturbation and preferential seeding of the m = 0 instability were studied in detail with fully kinetic plasma simulations performed in the Large Scale Plasma particle-in-cell code as well as with a simple snowplow model. The simulations showed that by employing an anode geometry with appropriate inner hollow radius, the neutron yield of the DPF is significantly improved and low-yield shots are eliminated.

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J. X. Liu, J. Sears, M. McMahon, K. Tummel, C. Cooper, D. Higginson, B. Shaw, A. Povilus, A. Link, A. Schmidt. 2016-10-28. Seeding the m = 0 instability in dense plasma focus Z-pinches with a hollow anode. https://arxiv.org/abs/1610.09092

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