Deuterium-fiber-initiated Z-pinches: Simulation compared to experiment

Deuterium-fiber-initiated Z-pinch experiments have been simulated using a two-dimensional resistive magnetohydrodynamic model^1,2 which includes many important experimental details, such as "cold-start" initial conditions, thermal conduction, radiation, actual discharge current vs. time, and grids of sufficient size and resolution to allow realistic development of the plasma. When the fiber becomes fully ionized (at a time depending on voltage ramp and fiber thickness), the simulations show rapidly developing m=0 instabilities drive intense non-uniform heating and rapid expansion of the plasma column. Diagnostics generated from the simulation results, such as shadowgrams and interferograms, are in good agreement with experiment³. Comparison of simulation-generated diagnostics with those from early experiments of this type suggests that shadow-gram images of the plasma were misleading indicators of the stability and rate of expansion of the plasma column. Terms often left out of the fluid model, such as the Hall term and the viscous stress tensor, may be significant in the Z-pinch^4,5. Progress will be reported on the addition of such terms to the simulation.