Control of current distribution by ICRF-enhancement of beam-driven current

Beam-driven currents can be enhanced by ICRF-heating of the beam-ions carrying the currents, because the slowing down time of these fast ions for the thermalization is effectively extended by the ICRF-acceleration. The ICRF-enhanced portion of the driven currents have usually a spatial distribution different to that of the pure beam-driven current. The driven currents are estimated with 1-D model taking into account neo-classical corrections on the contribution of electron-currents. The calculation of the current-distributions, presented here, has shown that changing the ratio between the NBI and ICRF wave powers allows us to control the current-profiles in Tokamaks. (author)