Nonlinear bounce-gyrokinetic formulation of Neoclassical Tearing Modes

The nonlinear bounce-gyrokinetic formulation of neoclassical tearing modes in axisymmetric tokamak geometry is presented. The guiding-center/gyrocenter and bounce-center/bounce-gyrocenter phase-space transformations are successively introduced in order to self-consistently describe the nonlinear bounce-gyrocenter dynamics of trapped/passing-particle orbits in axisymmetric tokamak geometry in the presence of a magnetic-island perturbation. The bounce-gyrokinetic Poisson (i.e., quasineutrality condition) and parallel Ampere equations are written explicitly in terms of magnetic flux-surface-averaged expressions that clearly highlight the role of the reduced polarizations that result from dynamical reduction. This work generalizes previous reduced kinetic descriptions of neoclassical tearing modes [1,2]. \\[4pt] [1] H.R. Wilson, J.W. Connor, R.J. Hastie, and C.C. Hegna, PoP {\bf 3}, 248 (1996).\\[0pt] [2] J.W. Connor, R.J. Hastie, and P. Helander, PPCF {\bf 51}, 015009 (2009).