Experimental measurements on FuZE-Q and scaling of sheared-flow-stabilized (SFS) Z-pinches at Zap Energy

Zap Energy is actively developing the sheared-flow-stabilized (SFS) Z-pinch concept for fusion energy applications with its currently operational FuZE-Q device. Sheared-flow stabilization offers a pathway toward long duration (~ 100 microseconds) Z-pinch plasmas that are stable to the m = 0 ‘sausage’ and m = 1 ‘kink’ MHD modes characteristic of static configurations. Sheared-flow stabilization provides for a more attractive trajectory towards a commercial Z-pinch fusion energy system by avoiding the need to embed an axial magnetic field with external coils or employ a close-fitting conducting wall around the plasma column. An experimental suite of diagnostics has been deployed on FuZE-Q, a next-generation SFS Z-pinch device designed to produce deuterium plasma conditions consistent with deuterium-tritium (DT) scientific breakeven Q = 1 (i.e., DD net-equivalent).These diagnostics include magnetic probes and current Rogowski coils, spectroscopic systems (e.g., broadband visible, ion Doppler, extreme ultraviolet (EUV), optical Thomson scattering (OTS), 633 nm and digital holographic interferometry (DHI), high-speed cameras, neutronics (e.g. plastic scintillators and LaBr₃ activation detectors), X-ray detectors, among others. Experimental results from the operational FuZE-Q device will be presented from various diagnostic systems. The methodology for the calculation and measurement of scientific gain in a SFS Z-pinch with fielded diagnostics will be provided, including the SFS Z-pinch Plasma OPerating Contour (POPCon) and assessing the impact of impurities and profile effects on scaling to scientific breakeven.