Momentum Transport in DIII-D Discharges with and Without Magnetohydrodynamics (MHD) Activity

Two phases of a DIII-D discharge with and without magnetohydrodynamics (MHD) activity are analysed using ONETWO code. The toroidal momentum flux is extracted from experimental data and compared with the predictions by neoclassical theory, Gyro-Landau fluid transport model (GLF23) and Multi-Mode model (MMM95). It is found that without MHD activities GLF23 and MMM95 provide a reasonable description while with MHD activity no model alone can fully describe the experimental momentum flux. For the phase with MHD activity a simple model of resonant magnetic drag is tested and it cannot fully explain the plasma slowing down observed in experiment.