Multi-ion plasmas in astrophysics

Abstract

The steady-state motion of a quasi-neutraln-ion plasma is investigated using a fluiddynamical model. The main results obtained are that there are only two distinct ways in which such a plasma can make a transition from a subsonic state to a supersonic one. There is one unique possibility for which there exists one critical point where all the ion gases have their Mach numbers exactly to unity and where the individual ion forcing functios (the inhomogeneous terms) are non-zero but linearly related to each other. The other possibility which we find is that at a critical point all inhomogeneous terms are identically equal to zero and there exist as many critical points as there exist simultianeous zeros of the ion forcing functions. These results are necessary and sufficient forn≥3. For one- and two-ion plasmas special results can be obtained, some of which fit into the above two classes and some of which do not.