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The resonant interaction between energetic-particles and tearing mode is an unresolved physics issue at present. It is found for the first time in tokamaks that an unstable tearing mode with slowly rotating m/n  =  2/1 helicity, where m/n represent poloidal/toroidal mode-numbers, interacts with energetic-ions and results in amplitude-bursting/frequency-chirping fishbone-like activities. Nonlinear hybrid kinetic-MHD simulations with M3D-K code prove that the co-passing energetic-ions are responsible for the drive of tearing modes, and the wave-particle resonance condition is satisfied at , where , and are the toroidal, poloidal angular frequencies of energetic-ions and the mode frequency respectively. These findings can help the understanding of tearing mode induced energetic-particle loss and particle acceleration during the tearing mode reconnection in laboratory and space plasmas. [ABSTRACT FROM AUTHOR]

We report an experimental result on the stabilization of the energetic–ion driven internal kink mode (ion fishbone) by electron cyclotron resonance heating (ECRH), observed for the first time in a toroidal plasma. The mode asserts itself a resistive branch close to the marginal stability point. The resulting fishbone mode depends not only on the injected power but also on the radial deposition location of ECRH, and the instability can be completely suppressed when the injected ECRH power exceeds certain threshold. Analysis by the fishbone dispersion relation, including the resistive effect, suggests that the magnetic Reynolds number plays a key role in the mode stabilization—it weakens the mode growth-rate and enhances the critical energetic–ion beta without changing the energetic–ion population. This ion fishbone stabilization mechanism can be important for future devices such as ITER, which has significant ECRH capability. [ABSTRACT FROM AUTHOR]