Ion correlations and ion microfields at impurities in dense plasmas.

An impurity placed in a plasma modifies the particle-particle correlations in the plasma. This impurity-plasma-plasma correction is relevant to ion-microfield calculations in hot dense plasmas as well as to models of the fractional quantum Hall excitations in terms of impurity-plasma systems. We show how to calculate such impurity-plasma-plasma corrections and apply them to a calculation of the Baranger-Mozer {BM) second-order microfield at He, Li, Be, and B impurities in a hydrogen plasma. Such a calculation for a dense plasma requires a definition of the electric field at the impurity due to an individual plasma ion in the plasma. We show how the traditional uniform jelli-