Theory of generation of kinetic Alfven waves by Non-conventional Global Alfven Eigenmodes

The process of radiation of kinetic Alfven Waves (KAWs) by a non-conventional global Alfven eigenmode (NGAE) or a reversed-shear Alfven eigenmode (modes which exist above maxima of Alfven continuum branches) is studied analytically and numerically. The Schrodinger equation describing a localized NGAE and emitted KAWs in the space of radial wave number is derived. Analytical expressions for the mode eigenfrequencies, the radiative damping rates and the wave amplitudes are obtained. The results obtained analytically are in agreement with those obtained numerically by means of two codes based on different methods. It is found that the amplitude of the radiated KAWs can be as large as the amplitude of the radiating mode, with the radiative damping rate being rather small.