ABSTRACT:A model to study atomic systems immersed in Debye plasmas is presented. Our model proposes a many-electron wave function built from analytical solutions for Yukawa potential. The variational principle is used considering the energy as a function of two new parameters: an average charge σ and the difference λ between the nuclear and a dual charge. As an application we have calculated ground state energies for He-like series for various Debye parameter q. Critical values q * are determined for which the bound-unbound transitions occur and comparison with other results in the literature are made.