Toroidal Rotation Braking with Low n External Perturbation Field on JET
Plasma toroidal rotation in a tokamak is of great importance for plasma confinement, because of its stabilization effects on Resistive Wall Modes (RWMs) and Neoclassical Tearing Modes (NTMs) and its shear stabilization effect on turbulence. External perturbation magnetic field have been frequently used to actively control or mitigate Edge Localized Modes (ELMs) on many tokamaks. It was also used to feedback control RWMs. However, both resonant and non-resonant component of the perturbation field can influence the plasma rotation. Non-resonant magnetic braking effects have been reported from many tokamaks recently.