Collective Thomson Scattering Measurement of Pressure and Flow Profiles on a Sheared-Flow-Stabilized Z Pinch

A collective Thomson scattering (TS) diagnostic measures electron temperature, density, and bulk flow profiles. At Zap Energy, both FuZE and FuZE-Q sheared-flow-stabilized Z-pinch experiments use TS diagnostics to track the evolution of sheared flow profiles. The electron plasma wave (EPW) component from TS is used to measure electron temperature (T_e) and electron density (n_e), while the ion acoustic wave (IAW) component is used to determine flow velocity. Measurements include peak n_e profiles >10²⁴ m^-3, ion flow velocity in the range of 150 km/s, and T_e in the range of multiple keV [1, 2]. The 532 nm diagnostic laser can split its 8-J pulse into two 4-J pulses for dual time-point measurements. A Bayesian framework analyzes the data, accounting for intensified CMOS sensor noise and intensity saturation. The results on electron pressure and flow profiles from the Z-pinch devices will be presented.

[1] U. Shumlak et al., Fusion Science and Technology 80 (1) 1-16 (2024).

[2] C. Goyon et al., Phys. Plasmas, 31(7), 072503 (2024).