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MHD simulation of plasma compression experiments

Presentation Abstract

Speaker: Meritt Reynolds (General Fusion): General Fusion (GF) is working to build a magnetized target fusion (MTF) power plant based on compression of magnetically-confined plasma by liquid metal. GF is testing this compression concept by collapsing solid aluminum liners onto plasmas formed by coaxial helicity injection in a series of experiments called PCS (Plasma Compression, Small).

We simulate the PCS experiments using the finite-volume MHD code VAC. The single-fluid plasma model includes temperature-dependent resistivity and anisotropic heat transport. The time-dependent curvilinear mesh for MHD simulation is derived from LS-DYNA simulations of actual field tests of liner implosion.

In previous work the 3D MHD simulations reproduced the appearance of n=1 mode activity in experiments performed in negative D-shape geometry (MRT and PROSPECTOR machines) and predicted better stability during compression in positive D-shape geometry similar to most spherical tokamaks (SPECTOR machine). Here we discuss simulations of the recent SPECTOR experiments PCS13 and PCS14 and the upcoming experiment PCS15.

Comparison of simulated Mirnov and x-ray diagnostics with experimental measurements will be presented, showing that PCS14 compressed well to a linear compression ratio of 2.5:1. Simulation indicates that the electron temperature rose from from 200 eV to 300 eV and the plasma pressure increased by more than a factor of 10.

M. Reynolds, S. Barsky, and P. de Vietien. MHD simulation of plasma compression experimentsExploratory Plasma and Fusion Research Workshop, Vancouver, Canada. August 3, 2017