Identification of intrinsic torques in ASDEX upgrade H-mode plasmas

Dedicated intrinsic torque experiments using a novel 2Hz NBI modulation technique have been performed for the first time in AUG. The analysis method to extract the intrinsic torque from plasma with any arbitrary NBI power has been optimised for the 2Hz NBI modulation technique. A 4-point plasma current scan with q95 ranging from 4 up to 11 was performed. The integrated intrinsic torque increases from 1.5Nm at Ip=0.4MA to 4Nm at Ip=1.0MA. The intrinsic torque profile is quite broad, most of it originating at ρ>0.5. With increasing plasma current, the pedestal height also increases significantly, making it impossible to distinguish whether the increased intrinsic torque drive originates from the changes in q or pedestal height. The effect of ECRH was studied in two 600 kA H-mode plasmas by injecting ECRH in the latter half of the NBI heated discharge. All the evidence indicates that the experimental data is best reproduced with a combination of off-axis counter-current torque (and possibly a small co-intrinsic torque in the centre at ρ<0.2) together with outward convection around the radius where the ECRH power is deposited. The present intrinsic torque profiles have quite large error bars and the profiles will change a bit when taking into account the small time variation in the confinement time due to modulation.