Optical spectra of hydrogen plasma at electron concentrations above 1019 cm?3

The optical spectra of a dense (nonideal) plasma formed in a pulsed discharge in a closed quartz capillary were studied. The emission spectra of pure hydrogen plasma at a temperature of 23000 K and an electron concentration of ～1.5×10¹⁹ cm^?3, twice the value achieved earlier, were obtained. The plasma diagnostics was carried out by spectroscopic methods taking into account the radial inhomogeneity of the plasma column. The spectral intensity measured in the Balmer region (300–800 nm) was found to be lower than that calculated by the model of weakly nonideal plasma, an effect not observed at lower densities. Possible reasons for the discrepancy between the experiment and the calculation were considered. One of them being the specific density effect of a relative rise in plasma transmission with increasing density.