Asymmetry of Stark profiles - The microfield point of view

The theoretical basis is presented that allows to compute the Stark broaden ed line shapes of atomic ions up to the quadrupole terms in the interaction potential between the radiator and the plasma electric microfields and the ir gradients. The nature of the corrections due to the plasma polarization effects associated with the electron distribution around ion perturbers are carefully analyzed. The relevant universal plasma functions are evaluated in a cluster expansion or by Monte Carlo simulations, and the line shape is calculated with ion dynamic effects by the Model Microfield Method. The as ymmetry of the Lyman alpha line of hydrogenic ions is then studied.