Measurements of the Stark Broadening of Hγ

The Stark broadening of Hγ has been investigated in three independent experiments covering the temperature range 1 «= kT «= 2 eV and electron-density range from 2 x 1O16 to 2 x 1O17 cm3. Two of the experiments used a gas-driven shock tube as the spectroscopic source, while the third used an e1ectromagnetically driven T-tube. The data were reduced by fitting the experimental intensities in the lines Hβ and Hγ to the theoretical profiles of Kepple and Griem. In both cases good agreement was found between theoretical and experimental profiles from the line center down more than an order of magnitude in intensity out into the wings. The mean ratio of the electron density determined from the Hγ profile to that determined from Hβ was 1.01, with a standard deviation of ~11 percent and a standard deviation of the mean of ∼ 2 percent