Effects of Initial Gas Injection on the Behavior of a Sheared-Flow Z-Pinch

A fusion thruster based on a flow-stabilized Z-pinch holds promise as a high-power, high-specific-impulse space thruster. Several challenges must be met in the development of a Z-pinch space thruster, one of which is preventing the destruction of the Z-pinch by classical magnetohydrodynamic instabilities. Linear stability analysis has shown that flow shear could limit the destructive eects of these instabilities. This result is supported by experimental measurements made on the ZaP Flow Z-Pinch Experiment, which has formed sheared-flow Z-pinch plasmas that exhibit characteristics of stability for over one thousand theoretical instability growth times. A second challenge is designing the thruster to withstand the power load from the fusion reaction. A deuterium-tritium-fueled Z-pinch operating at a temperature of 15 keV is estimated to have a peak fusion power density of 2 ◊ 10 16 W/m 3 , which would be dicult to handle in steady-state. Pulsed operation of the thruster would reduce the energy-handling requirements.