Kink Mode Study in EAST High-β_p Plasma

Full text: Two types of kink modes, fishbone and long-lived mode are experimentally and numerically studied at EAST tokamak. In high-β_p plasma, sawtooth instability was replaced by a saturated 1/1 internal kink mode which either manifests itself as a periodical burst energetic ion related fishbone or as a long-lived mode which is associated to the core safety factor at q₀ ∼ 1. The present of those 1/1 internal modes are beneficial for sustaining the hybrid scenario with extended regions of low-magnetic shear profile and q₀ ∼ 1, because of that they can expel high-Z impurity and can make flux pumping. The mechanism responsible for the flux pumping caused by kink modewas numerically in nonlinear 3D magnetohydrodynamic simulations using the M3D code. Furthermore, M3D+K code hybrid simulation shows a good agreement to the fishbone activity in EAST. (author)