High resolution digital holographic interferometry on the FuZE Fusion Z-Pinch Experiment

The recently constructed sheared flow stabilized (SFS) Z-pinch experiment, the Fusion Z-Pinch Experiment (FuZE), is operational. The experiment is investigating scaling of SFS Z-pinch plasmas towards fusion conditions. Cylindrical plasmas are compressed to small radii ($< 1$ cm), and high densities ($> 10^{18}/$cm$^3$) as plasma current is increased. Diagnosing the size, density and internal structure of these small radii cylindrical plasmas require a high spatial resolution plasma density diagnostic. Motivated by this, a holographic interferometer with 10 micron spatial resolution has recently been installed on FuZE [1]. A Nd:YAG laser is used with a digital camera to produce holograms from the plasma assembly region. Digital holograms are numerically reconstructed to obtain chord-integrated electron density of compressed plasma, with fine spatial resolution. Assuming cylindrical symmetry in the assembly region, plasma radial density profiles are reconstructed from these chord-integrated electron density data. Both chord-integrated and radial plasma density data from FuZE are presented. [1] M.P. Ross & U. Shumlak, RSI 87, 103502 (2016)