Electron Dynamics Associated with Stochastic Magnetic and Ambipolar Electric Fields

A conservative transport operator in ($r$,$v_{\parallel }$,$v_{\perp }$) space and moment equations are derived which describe the combined effects of a stochastic magnetic field and a radial electric field on the electrons. The transport operator is coupled with Fokker-Planck and Ohmic-heating terms to compute the distribution function. A physical picture emerges which emphasizes the possible importance of the ambipolar potential ($\sim \frac{T_e}{e}$) and plasma boundary physics in determining overall plasma confinement.