Equilibrium Diffusion in a Toroidal Resistive Plasma

The equilibrium equations are solved, including resistivity, parallel viscosity, and a radial electric field. A resonance effect occurs when the frequency of the electric rotation about the minor axis approaches the frequency of a natural plasma mode. For arbitrary steady electric fields the ion and electron diffusion rates are unequal, and the space charge inevitably builds up until the two rates equalize. In most conditions of interest, this ambipolar electric field is close to the resonance value, and the ambipolar diffusion rate is much larger than the Pfirsch and Schlüter rate.