Abstract
The collective and plasma screening effects on the Wannier universal threshold law for the double-electron escape into the continuum are investigated in nonideal plasmas. The screened re-normalized electron charge is obtained as a function of the nonideality plasma parameter, Debye length, and charge of the residual ion. The screened threshold exponent of the double-ionization cross-section is obtained by using the effective charge. It is found that the nonideal collective effect reduces the renormalized electron charge, especially in the intermediate distance region. It is also found that the screened Wannier exponent increases with increases of the nonideality plasma parameter and Debye length. In nonideal plasmas, the plasma screening effect is found to be more significant than the collective effect.