Parameters of calcium and titanium plasmas obtained using different focusing geometries of laser radiation

A comparative study was made of the far vacuum ultraviolet spectra of calcium and titanium plasmas obtained by point, circular, and linear focusing of laser radiation on a plane target. The titanium spectra were obtained with a spatial resolution along the normal to the target. The relative intensities of 2s2pⁿ⁺¹–2s²2pⁿ transitions in ions isoelectronic with the F, O, N, and C atoms were used to determine the ion composition and ionization temperature T_Z. The concentration of the Ne-like ions was found by extrapolation. The ion composition of the titanium plasmas was determined as a function of the distance to the target. When linear focusing was used, the plasma radiation was restricted to a region much lower in height than in the point and circular focusing cases.