Analytic continuation for the generalized Bohm criterion in a two-ion-species plasma

The generalized Bohm criterion in a two-ion-species plasma is analytically investigated. The universal iterative formulas of the approximative solutions have been affirmed for the ion acoustic wave (IAW) dispersion relation and the generalized Bohm criterion in the two-ion-species plasma for the first time. For a weakly collisional two-ion-species plasma, it is indicated that the choice of the initial solution and the repetitious iterative operation for the ion drift velocities is the linchpin of the optimized solution for the ion acoustic wave dispersion relation and the generalized Bohm criterion, considering the more general case and extensive physical characteristics.