Population inversion, which occurs in a recombining plasma when a stationary He plasma is brought intocontact with a neutral gas, is examined. With hydrogen as a contact gas, noticeable inversion between low-lying levels of H has been found. The overpopulation density is of the order of 108 cm-3, which is much higher than that (≃ 105 cm-3) obtained previously with He as a contact gas. Relations between these experimental results and the conditions for population inversion are discussed with the CR model.
© 1980 Optical Society of America
Masamoto Otsuka, "Population inversion in a stationary recombining plasma," Appl. Opt. 19, 3904-3910 (1980)