Resonance destabilization of fast magnetoacoustic eigenmodes by trapped particles and ion cyclotron emission in tokamak reactors

Edge localized magnetoacoustic-cyclotron instability excited through bounce resonances with the fast ions is shown to be consistent with the spectrum of ion cyclotron emission in tokamaks. In particular, it is shown that the instability growth rate is maximum and vanishes for a wave frequency close to the cyclotron harmonics of fast ions near the outer and inner circumferences of the torus, respectively. The analysis takes into account both the radial structure of the eigenmodes and the finite orbit width of fast ions.