Derivation of radial electric fields using kinetic theory in tokamak

Abstract

In the current study, radial electric field with fluid equations has been calculated. The calculation started with kinetic theory, Boltzmann and momentum balance equations were derived, the negligible terms compared with others were eliminated, and the radial electric field expression in steady state was derived. As mentioned in previous researches, this expression includes all types of particles such as electrons, ions, and neutrals. The consequence of this solution reveals that three major driving forces contribute in radial electric field: radial pressure gradient, poloidal rotation, and toroidal rotation; rotational terms mean Lorentz force. Therefore, radial electric field and plasma rotation are connected through the radial momentum balance.