Diffusion in Toroidal Plasmas with Radial Electric Field

The equilibrium of an axisymmetric toroidal plasma is analyzed. In the resistive regime the diffusion rate derived by Pfirsch and Schl\"uter is modified when the plasma rotates about its minor axis because of electric drift. In the weakly collisional regime the electron-diffusion rate is greater than that derived by Galeev and Sagdeev, except in the ambipolar condition where the diffusion rate is comparable with theirs.