Role of Toroidal Rotation in ITB Formation in Tokamaks

A set of tokamak discharges with internal transport barriers (ITBs) are studied using the TRANSP code in order to investigate the role of toroidal rotation in triggering of ITBs. The toroidal momentum transport is predicted using theory-based Multi-Mode and TGLF anomalous transport models to compute the toroidal rotation profiles and\ua0 the effects of turbulence quenching as a result of associated sheared flows.\ua0 The effect of co- versus counter injected beams on the location and strength of ITBs is studied. Results are presented for existing discharges in order to illustrate the extent to which the Multi-Mode and TGLF models in TRANSP code yield toroidal rotation profiles that are consistent with experimental data. The comparison is quantified by calculating the RMS deviations and Offsets. The self-consistent evolution of the equilibrium is computed using the TEQ module.\ua0 Neoclassical transport is calculated using the Chang-Hinton model. NBI and ICRF heating and current drive are obtained using the NUBEAM and TORIC modules. Supported by US DoE Grant DE-SC0013977 and DE-FG02-92ER54141