Investigations of LHCD induced plasma rotation in Tore Supra

Theoretical investigations are performed in order to explain the plasma rotation increments induced by lower hybrid current drive (LHCD) in Tore Supraand the results are compared to the experimental observations. The intrinsic toroidalrotation is governed by several mechanisms in concert. The impact of the LHCD on each involved mechanism is analyzed. The neoclassical toroidalrotation is always in the counter-current direction. The toroidal diamagneticvelocity is of the order of the experimental toroidalvelocity. At high plasma current the rotation evolution in the lower hybrid (LH) phase is controlled by the neoclassical friction force due to the trapped ions in banana trajectories through the toroidal diamagneticvelocity. This force results in the counter-current increment as observed in the experimental measurement of toroidalrotation. At low plasma current the rotation is dominated by momentum turbulent transport when the LH waves are applied. The Reynolds stressgrows strongly compared to the high plasma current case and acts as a co-current force through its residual stress contribution. Momentum transport simulations are also performed with CRONOS (Artaud et al 2010) in order to assess the rotation increments induced by LHCD.