SIMULATIONS OF CURRENT-DENSITY PROFILE CONTROL USING LOWER-HYBRID CURRENT DRIVE IN THE TDEV TOKAMAK

The physics basis of a simulation model for lower hybrid current drive (LHCD) is discussed. Issues associated with LH power deposition - wav e propagation, mode conversion and cut-offs in toroidal geometry, as w ell as linear and quasi-linear Landau damping - are analysed. A simula tion model (ACCOME) is applied to the LHCD experiment now operating on the Tokamak de Varennes (TdeV). The profiles and values of density an d temperature needed as inputs to ACCOME are taken from the experiment . The predictions of current density and loop voltage from ACCOME are then compared with experimental LHCD results. Possible LH current prof ile control experiments are also analysed for TdeV using composite LH spectra to control the location of RF power deposition. Finally the re levance of these current profile control results to future devices is discussed and an example is shown for ITER-like parameters.