Laser plasma diagnostics using Balmer series transitions

Spatially resolved spectra and photographs of a carbon jet in the radiation of the far vacuum ultraviolet lines were obtained for laser radiation focused onto a planar target using different geometries. The fine structure of the H_α transition of a CVI ion was observed. The profile of the electron density N_e was deduced from the Stark broadening of Balmer series transitions. The expansion velocity was measured and estimates were made of the electron temperature, plasma ionization state (the ratio [CVII]/ [CVI]), rate of evaporation of the target material, and acceleration at an early stage of the expansion. The gradient of N_e in the vicinity of the critical point was estimated. The feasibility of determining N_e from the Stark broadening of Balmer series transitions in hydrogen-like ions over a broad density range is discussed.