Optical Measurements of Electron and Ion Density and Temperature of a Z-Pinch Plasma During Pre-Compression

Previous measurements[1] of plasma parameters on Z-pinch devices have focused on ion and electron velocities and temperatures during compression and the associated fusion production, reporting keV ion temperatures and densities in the range of 10²³ m^-3. New measurements of ion temperature, ion velocity, and electron density and temperature have been carried out in the pre-compression acceleration phase. High resolution visible (VIS) spectroscopy was employed to collect emission of deuterium and deuterium-doped plasmas at multiple locations during the temporal evolution of the Z pinch (breakdown, acceleration, and pre-compression). Electron density, ion velocity, and ion temperature were inferred from Stark broadening, Doppler shift, and Doppler broadening, respectively. Broadband spectroscopy collected UV-VIS spectra in the same location and time. These spectra were matched with collisional-radiative modeling to infer electron density and temperature. Initial results show that plasma density and temperatures vary with device settings and can be tuned.

1: B. Levitt et al., Phys. Rev. Lett. 132, 155101