A Gyrokinetic model in the long wavelength regime

Miyato, Naoaki; Scott, B. D.*; Yagi, Masatoshi

Since perturbations with short wavelength and small amplitude are considered in the standard gyrokinetic formulation, there is no reason why the standard model is still valid in the long wavelength regime. So far, we clarified by reviewing the gyrokinetic formulation in the electrostatic limit that the high-order displacement vector associated with the guiding-centre transform, which is neglected in the standard formulation, should be considered in the long wavelength regime. This time we reconsider the electromagnetic gyrokinetic model with shear Alfvn perturbation () in which the parallel canonical momentum () is one of velocity variables. The symplectic part of the model has the same form as the electrostatic one and we can apply the same guiding-centre transformation as the electrostatic case. However, the gyrokinetic Hamiltonian is modified by the magnetic perturbations.