Bounded multicomponent plasmas and generalized Bohm criterion

A multi-fluid model for bounded plasmas containing p≥1 positive species of ions yields a p+2 point boundary value problem (BVP) if steady state conditions, space charge effects and simple geometries are taken into account. A three point BVP results if the space charge effects are neglected. Assuming cold ions a two point one follows in both the cases. Without space charge effects a generalized Bohm criterion can be formulated. The number of boundary points is not increased if negative ions are included