ИСТИНА

The invariance of plasma evolution equations under some transformations allows to model plasma jets interaction in astrophysical objects by plasma which is generated by laser systems during irradiation massive solid targets. Ionization state of expanding laser plasma is non-stationary in the most of cases. Such plasma is overcooled so it is recombining one. In this regard, development of the recombining plasma diagnostics methods is one of the directions in laboratory astrophysics. Intensity ratios of resonance lines of He-like 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. So plasma diagnosing can be held by comparing of ratios obtained from the real plasma spectrum and calculated values. Calculations were carried out for F VIII ions. Intensity ratios are sensitive to the density in the range of 10^(16) − 10^(20) cm^(−3) while the temperature ranges from 10 to 100 eV for ions. With help of them parameters of plasma jets created by nanosecond laser system ELFIE (Ecole Polytechnique, France) for astrophysical phenomenon modelling were determined. Obtained dependencies are quite universal and can be used for any recombining plasma containing He-like fluorine ions. Spectral lines of another He-like ions also can be used in case of another density range. Probabilities of atomic transitions in He-like ions should be scaled similar to H-like ions along the isoelectronic sequence. So, the method‘s sensitive to temperature and density regions should be shifted proportionally to (Zn − 1)^2 and (Zn − 1)^7 correspondingly