ITER Baseline Scenario with ECCD Applied to Neoclassical Tearing Modes in DIII-D
POSTER
Abstract
The neoclassical tearing mode (NTM) is a magnetic island that can occur on flux surfaces where the safety factor $q$ is a rational number. Both m/n=3/2 and 2/1 NTM's degrade confinement, and the 2/1 mode often locks to the wall and disrupts the plasma. An NTM can be suppressed by depositing electron cyclotron current drive (ECCD) on the $q$-surface by injecting microwave beams into the plasma from gyrotrons. Recent DIII-D experiments have studied the application of ECCD/ECRH in the ITER Baseline Scenario. The power required from the gyrotrons can be significant enough to impact the fusion gain, $Q$ in ITER. However, if gyrotron power could be minimized or turned off in ITER when not needed, this impact would be small. In fact, tearing-stable operation at low torque has been achieved previously in DIII-D without EC power. A vision for NTM control in ITER will be described together with results obtained from simulations and experiments in DIII-D under ITER like conditions.
*Work supported by the US DOE under DE-FC02-04ER54698, DE-AC02-09CH11466, DE-FG02-04ER54761.