Determination of the electron density profile of a laser plasma from the Stark broadening of spectral lines in vacuum ultraviolet

Measurements were made of the Stark broadening of the H_α(182.17 Å) and H_β(134.95 Å) lines of the C VI ions at various distances from a target in a plasma formed as a result of focusing of radiation on this target. The target was a planar slab of carbon and the laser radiation was focused into a spot 800 μ in diameter where the average power density was q~8×10¹¹ W/cm². The electron density N_e profile was determined over distances of 0–250 μ from the target. A plasma with a low N_e, gradient could form in a confined space. The refraction of far vacuum ultraviolet radiation was considered allowing only for the electron component of the plasma.