Alfvén wave heating, current drive, plasma flow and improved confinement scenarios in tokamaks

Theoretical results on Alfvén wave (AW) heating, current drive and plasma flow, which may be relevant for improved confinement scenarios, are presented. It is shown that a small population of light impurities, such as carbon, in a hydrogen plasma can strongly modify the dispersion of global Alfvén waves and the Alfvén continuum. The current drive and plasma flow induced by AWs are studied for magnetized weakly collisional plasmas. We find that plasma flow and ion banana orbit squeezing by the radial electric field shear induced by AWs may be a convenient trigger for the formation of transport barriers in tokamaks. These effects are explored via a series of numerical calculations for the heating conditions foreseen for the tokamak chauffage Alfvén wave heating experiment in Brazil (TCABR).