ABSTRACT
The summary of magneto-hydrodynamics (MHD) theory was heuristic and based on some common sense arguments. Complex plasma states with many different types of ions, negative ions, partial ionization, etc., can be seen as generalizations, so to be specific the authors consider a mixture of an electron and an ion gas, where the ion charge is of the same magnitude as the elementary electron charge but with opposite sign. The obvious example is a fully ionized hydrogen gas. The authors find that the MHD continuity equation is trivially recovered, by the proper interpretation of the bulk plasma flow velocity. The motion of charged particles in a given magnetic field is such as to produce a magnetic perturbation in the opposite direction to the imposed field; this is at times called Lenz’s law. Plasma is a diamagnetic medium due to this effect.
