Boundary Intrinsic Velocity in DIII-D H-modes

The toroidal velocity, $V_\phi$, in the pedestal region of DIII-D H-mode discharges with negligible neutral beam injected (NBI) torque is nonzero, in the direction of the plasma current, co-$I_p$. This velocity is found to scale approximately linearly with the local ion temperature, $T_i$. Such a scaling can result simply because of thermal ion loss from the pedestal region; counter-$I_p$ thermal ions are predominantly lost leaving a net co-$I_p$ local average velocity. However, we also measure $V_\phi \sim T_i$ well inside of the pedestal region, where classical thermal ion orbit loss would not be effective. This could be explained by a toroidal momentum pinch with pinch velocity proportional to the gradient of $T_i$. There are theories that predict such a pinch driven by turbulence. We have used the GYRO code to investigate the scaling of the turbulent pinch effect in conditions typical of the edge region of these intrinsic H-mode discharges.