title: Kinetic effects of energetic particles on resistive MHD stability.
abstract: We show that the kinetic effects of energetic particles can play a crucial role in the stability of the m/n=2/1 tearing mode in tokamaks (e.g., JET, JT-60U, and DIII-D), where the fraction of energetic particle beta(frac) is high. Using model equilibria based on DIII-D experimental reconstructions, the nonideal MHD linear stability of cases unstable to the 2/1 mode is investigated including a deltaf particle-in-cell model for the energetic particles coupled to the nonlinear 3D resistive MHD code NIMROD [C. C. Kim et al., Phys. Plasmas 15, 072507 (2008)10.1063/1.2949704]. It is observed that energetic particles have significant damping and stabilizing effects at experimentally relevant beta, beta(frac), and S, and excite a real frequency of the 2/1 mode. Extrapolation of the results is discussed for implications to JET and ITER, where the effects are projected to be significant.
authors.affiliation: Department of Physics and Engineering Physics, University of Tulsa, 800 South Tucker Drive, Tulsa, Oklahoma 74104, USA.
authors.forename: R
authors.initials: R
authors.lastname: Takahashi
authors.forename: D P
authors.initials: DP
authors.lastname: Brennan
authors.forename: C C
authors.initials: CC
authors.lastname: Kim