A RELATIVISTIC THEORY OF ELECTRON CYCLOTRON CURRENT DRIVE EFFICIENCY

A fully relativistic theory of electron cyclotron current drive (ECCD) efficiency based on Green’s function techniques is considered. Numerical calculations of the current drive efficiency in a uniform magnetic field are performed. The numerical results with parameter regimes relevant to ITER operation are compared with those of two simplified models in which the electronelectron Coulomb collision operator is respectively approximatedbyitshigh-velocitylimitandasemirelativistic form. Our results indicate that the semirelativistic approximation of the collision operator should be appropriate for modeling the ECCD efficiency under ITER conditions.