Balmer Series H (beta) Measurements in a Laser-Induced Hydrogen Plasma

Stark-broadened emission profiles of the Balmer series H(beta) lines are measured subsequent to nanosecond laser-induced optical breakdown in gaseous hydrogen. Electron number densities are found from time-resolved spectra from H(beta) emissions to be in the range 10^(15) -10^(18) cm^-3 . These results are compared with H(alpha) measurements for which number densities as high as 10^(19) cm^-3 are determined from Stark widths and Stark shifts. Good agreement is reported for number densities inferred from H(alpha) and H(beta) emissions, down to an electron number density 3 * 10^(16) cm^-3 , by accurate treatment of ion dynamics in the theory