Scaling of the Sheared-Flow Stabilized Z-Pinch: The Fusion Z-Pinch Experiment "FuZE"

The sheared flow stabilized (SFS) Z-pinch ZaP experiment was constructed based on calculations [1] showing stabilization of kink and sausage instabilities. ZaP experimentally demonstrated production and sustainment of an SFS Z-pinch for a wide range of plasma parameters, with densities up to $n=10^{23}$ m$^{-3}$ and a pinch radius of $a$=1 cm. [2-4] The SFS Z-pinch is resistant to the instabilities of conventional Z-pinches, yet maintains the same favorable radial scaling, making it an energy-efficient way to achieve fusion-relevant conditions. The ZaP-HD (high density) experiment has demonstrated scaling of the SFS Z-pinch to 2-3$\times$ smaller $a$ and 10$\times$ higher $n$. [5] Supported by ZaP and ZaP-HD, the Fusion Z-pinch Experiment (FuZE) project investigates scaling plasma parameters toward fusion conditions by decreasing $a$ 2-3$\times$ to 1 mm, and increasing $n$ 10$\times$ to 10$^{25}$ m$^{-3}$. The approach combines improved gas injection and flexible power supplies with the successful ZaP SFS Z-pinch formation. Detailed fluid and kinetic simulations complement the experimental studies to gain scientific insight into the plasma behavior and predict scaling to higher performance.