The plasma-sheath and its stability in a quiescent plasma containing two species of positive ion

The equations for a one-dimensional 'generationless' plasma containing two species of positive ion are derived and examined computationally in the steady state. When the ions have different masses, their drift speeds are different, and there is the potential for instability. This instability is examined here, in the locally uniform plasma approximation, for the situation of nearly collisionless plasmas. It is concluded that the situation may be weakly unstable and lead to the generation of noise near the plasma edge, but that the plasma parameters themselves are unlikely to be materially affected.