Spatio-temporally Resolved Magnetic Field Measurements in the ZaP-HD Flow Z-Pinch Device Using Zeeman Splitting

Abstract

The ZaP-HD shear-flow-stabilized (SFS) Z-pinch experiment has successfully proven that the instabilities of the simple Z-pinch plasma confinement scheme can be mitigated with sheared flow. Results from ZaP-HD have been used to develop and scale SFS Z-pinches towards high-density and high-temperature fusion conditions. Line radiation spectroscopy has provided insightful, data-rich measurements of a variety of relevant plasma parameters that help generate a greater understanding of the physics of the SFS Z pinch. Although spectroscopy measurements have been taken across the radius of ZaP-HD, these measurements have not been radially deconvolved to give a true picture of the interior of the Z pinch. Ion temperature and magnetic field strength, two critical parameters for better understanding the heating and current flows in ZaP-HD are measured using ion Doppler spectroscopy and Zeeman splitting techniques and are radially deconvolved. Uniform ion temperatures between 10-50 eV and current densities on the order of 50 $\mathrm{A/mm^{2}}$ are recorded across the radius of the pinch. Spectroscopic measurements of the pinch center and total pinch current are compared to in-situ b-dot probes. Some preliminary time-resolved and deconvolved measurements using a fast-framing ultra high-speed camera are taken and show general agreement with measurements taken by a single-frame ICCD camera.