Expansion of a multi-ion plasma into a vacuum

Numerical solutions of the Vlasov and Poisson equations for the expansion of a plasma with O+ and H+ as the constituent ions are presented. The self-similar nature of the expansion is examined by comparing the numerical results with available theories. The formation of a plateau in the expansion region, when the H+ ions are initially minor, is investigated by varying the electron to ion temperature ratio. The numerical results show that self-similarity holds in the quasineutral regions of the plasma