Analysis of Neutral Beam Current Drive for the International Thermonuclear Experimental Reactor

An analysis of the neutral beam (NB) current drive for the International Thermonuclear Experimental Reactor (ITER) is performed. The NB deposition profile for a model elliptic equilibrium is evaluated for arbitrary density profiles. Multistep ionization is accounted for. The NB current density is calculated by using an approximate solution of the Fokker-Planck equation. A parameter scan is performed by changing electron density, plasma temperature, the plasma effective ionic charge Z_eff, beam energy E_b, beam mass number, beam section, and tangency radius of the beam center. The largest values of the current drive figure of merit γ_NB = I_NBnR/P are obtained for the largest beam energy. The obtained value of γ_NB for the ITER reference scenario is γ_NB = 0.6 for E_b = 1.3 MeV and Z_eff = 2.