Localized global ICRF eigenmodes and conversion zones in a two-ion species tokamak

The location of the slow-fast wave conversion zones is analysed for a tokamak in ICRF. The obtained dispersion relation which determines the surfaces of wave conversion describes the cases of weak and strong mode coupling as well as the intermediate one. Using the same approach, the localized global eigenmodes are studied. With respect to their nature, they are separated into two types. The first is the TLE-TAE-like eigenmode. Like the TAE it is the result of mode coupling. The second one is the single-mode eigenmodes. This type is represented by two eigenmodes. One is the extension of the GAE (global Alfven eigenmode) to the two-ion species plasma. The other one is OHE (original hybrid eigenmode) which exists in the case of strong mode coupling. The field structure and dispersion of these waves are discussed. (Author)