Flow Z-Pinch Plasma Production On The Fuze Experiment

The Fusion Z Pinch Experiment (FuZE) investigates sheared-flow stabilization of classic m=0 and m=1 instabilities in Z pinches with an embedded axial flow. FuZE consists of a 100cm coaxial plasma accelerator, where neutral gas is ionized and accelerated in a pulsed electrical discharge, followed by a 50cm assembly region, where pinches are formed. Maintaining the pinch requires continuous plasma injection provided by a deflagration mode in the coaxial accelerator. Two discharge modes, with and without deflagration, are investigated on FuZE. Pinch formation is observed with deflagration only. Plasma velocities in the assembly region are found to match the ExB velocity estimated in the accelerator based on a 1D circuit model, indicating that a 1D MHD approximation may offer a valid description of the plasma in the accelerator channel. The velocity of magnetic field propagation is found to agree with the snowplow model based on momentum conservation, and the lifetime of the pinch is shown to be in agreement with constraints imposed by mass conservation.