INTERFERENCE OF RADIATING STATES AND ION DYNAMICS IN SPECTRAL-LINE BROADENING

The influence of the plasma coupling between the populations and the c oherences on the lineshape is investigated. Ion dynamics is taken into account. The present research is performed within the atomic density matrix formalism. Ion microfield dynamics is simulated by the kangaroo -Poisson stochastic process (model microfield method). Numerical calcu lations of both lifetimes of radiating states and lineshapes are perfo rmed for the spectral doublet (1s-2s)2(1)S-(1s-4p)4(1)P, (1s-2)2(1)S-( 1s-4d)4(1)D of helium-like multicharged ions in hot dense plasmas. It is found that the ion microfield essentially influences the difference of populations of radiating 4(1)P,4(1)D states. Calculation of the li neshape of the doubler (1s-2p)2(3)P-(1s-4d)4(3)D, (1s-2p)2(3)P-(1s-4f) 4(3)F of neutral helium at astrophysical plasma conditions is also per formed. The contribution of nonlinear interference effects (NIEF) in b oth allowed and forbidden components is calculated at various plasma c onditions and a comparison with binary adiabatic theory is made. The r esults demonstrate that it is essential to take account of NIEF in the calculation of lineshapes of: multicharged ions, but not essential in the case of neutral helium.