33 / 2021-04-09 22:23:14

The effects of 3/1 magnetic island on plasma flow in edge region of J-TEXT

plasma flow, intrinsic rotaion, RMP, penetration, magnetic island

Plasma rotation can stabilize macro-MHD instabilities and suppress turbulent transport which is the key to stable operation of tokamak under high parameters. For future fusion reactors, external momentum injection may not provide sufficient momentum. These facts highlight the importance of intrinsic rotation which exists even without external momentum injection. At present, it is most believed that the source of intrinsic rotation mainly comes from the edge of plasma. Many tokamaks develop the magnetic profile in edge region by the application of resonant magnetic perturbation (RMP).The study on the effect of magnetic islands which excited by RMP on plasma rotation helps to get further understanding on response of plasma to RMP and the mechanism which drive the plasma rotation.

The plasma poloidal rotation in edge region has been studied with the locked 3/1 magnetic island excited by the static RMP penetration. The 3/1 magnetic islands has effect on poloidal rotation of carbon III impurity and the shift of poloidal rotation after the penetration is correlated with the position of magnetic island. By scanning the RMP phase, it is found that the closer to the O-point of magnetic island, the larger the poloidal rotation of carbon impurities change. It may due to the asymmetry of plasma flow in the magnetic island which is similar to the cases of toroidal rotation. Therefore, the plasma flow is measured by coherence imaging spectroscopy system and it is also found to be effected by the occurrence of 3/1 magnetic islands as well.  And it shows differences when it comes to the different phases which is thought to be correlated with change of poloidal rotation.