Pressure ionization in dense plasmas

We present an atomic model for assessing pressure ionization in a dense, st rongly coupled plasma. The model is constructed in the framework of collisi onal-radiative equilibrium and detailed-configuration accounting, in which the effect of pressure ionization is described by the shift and broadening of energy levels. Its noteworthy feature is the use of a screening length b ased on a modified treatment of incipient Rydberg states. Using this model, we have identified signatures suitable for testing predictions of ionizati on balances and excited state populations, as well as a new approach for me asuring the opacity of an absorption line in a well-defined plasma state. [ S1063-651X(98)15712-4].