In general, a plasma, although neutral in total, contains species of different charges. All gases will change to a plasma at high temperatures due to ionization. As long as a continuum assumption is valid, a plasma can be described by the equations of Magnetohydrodynamics (MHD). They are developed by considering the conservation of mass, momentum and energy just as done for the Euler equations and taking into account Maxwell’s equations that describe the electric and magnetic field.