Electron temperature measurement from neutral atomic tungsten emission line ratio.

This article focuses on a method to determine absolute electron temperature in plasma by analyzing the intensity ratio of two neutral atomic tungsten emission lines at 400.88 and 401.52 nm. The technique was applied to the post-discharge region following a high-voltage nanosecond pulsed discharge in air between tungsten electrodes, with electron temperature measurements calibrated against laser Thomson scattering data. The study derived a calibration factor representing the ratio of Einstein A coefficients for these transitions, enabling electron temperature calculation from the tungsten line intensity ratio alone under the assumption of local thermal equilibrium. Additionally, the work assigned a previously unreported Einstein A coefficient for the 401.52 nm tungsten transition, supporting its use in future passive spectroscopic plasma diagnostics.