ИСТИНА

Laser produced jets are fully scalable to YSOs because of the plasma evolution equations invariance under some transformations. While the plasma created by powerful laser expands from the target surface it becomes overcooled, i.e. recombining one. So to improve diagnostic methods applicable for such plasma is rather important problem in laboratory astrophysics. Intensity ratios of x-ray resonance lines radiated by multicharged ions can be used for plasma diagnostics. Mentioned ratios can be calculated in terms of quasi steady-state approximation for the wide range of densities and temperatures. Comparing the ratios obtained from a real plasma spectrum with calculated values it becomes possible to evaluate plasma parameters. The method was applied to successfully interpret the spectra of F VIII ions emitted by laser plasma jet created from CF2 solid target irradiated by ns 10–60 J laser pulses. It was shown intensity ratios are sensitive to the density in the range of 1016–1020 cm−3 while the temperature ranges from 10 to 100 eV for ions. Method allowed to determine plasma parameters rather far from the target surface. Sensitivity of the method was proved to be enough to distinguish the difference between parameters of plasma jets for various geometries in the experiment.