Equation of state of high density deuterium and hydrogen plasmas : Different attempts to model screening of ion-ion interactions

Abstract
We investigated the electron screening of the ion-ion interaction in the range 1.7 ≤ rs ≤ 2.5 and 5000 ≤ T(K) ≤ 50000 characteristic of the last NOVA experiments on Deuterium. Exploring different approaches (RPA, TCP, Yukawa) in the framework of the Ross equation of state (linear mixing model), we arrived at the following trends : electron screening contributes significantly to the thermodynamics of Hydrogen (or Deuterium) at intermediate coupling and at partial degeneracy of the electrons. However, this effect is not large enough to fit in with the NOVA Hugoniot points. We also stress that the Yukawa potential, when considered as an effective potential, is a flexible and efficient tool grasping the main feature of the electron screening.