Method of measuring time-resolved electron density and ion temperature of plasmas with a fabry-perot etalon

Abstract

A method has been developed to measure the half-width of spectral lines with a time resolution better than 0.02 μsec. Electron density and ion temperature in the regions 1014 to 1016 cm-3 and 105 to 108 °K respectively can be obtained from the Stark and Doppler broadening of spectral lines. Using a Fabry-Perot etalon with a fixed spacing less than 1 mm, one can directly obtain the half-width from the ratio of the minimum and maximum intensity of the Haidinger pattern, assuming that the broadened spectral lines have a Voigt profile. Measurements of the electron density from Hβ were carried out in a linear θ-pinch discharge.