Experimental investigation of minority ion concentration in a weakly ionized hydrogen plasma

H 3 + and H 2 + ion minority concentrations in a weakly ionized hydrogen plasma are determined through the comparison between the measured wavelength of the neutralized in Bernstein waves and the theoretical one, given by the solution of the complete electrostatic dispersion relation. A simple model based on the resolution of fluid balance equations permits one to explain the presence of a high percentage of H 3 + ( approximately=30%).