Spectroscopic measurement of the electron temperature of a hypersonic plasma jet

The efficacy of a plasma liner formed by the merging of a spherical array of plasma jets in imploding a magnetized target plasma depends critically on its initial temperature. The lower is its temperature the greater is its imploding efficacy. In this paper, we report on the first spectroscopic measurement of the plasma jet as launched from a PJMIF-class plasma gun by the use of the line ratio method. Electron temperature is derived via spectral line ratio analysis of Ar II, supplemented by other diagnostics such as photodiode arrays operating on the nanosecond scale for the first time. Verification of our findings is conducted through comparison with electron temperatures inferred from PrismSPECT simulations. In the initial operating capability test series, electron temperatures around 1 eV are observed, aligning with the anticipated performance of the plasma gun. The remarkable repeatability across successive shots establishes a robust platform for subsequent investigations.