The nonlocal radio-frequency response of a toroidal plasma

For the first time, a model of the nonlocal plasma radio-frequency response has been developed which, while using standard guiding centre variables, achieves the same high level of symmetry as Hamiltonian descriptions. The full richness of particle motion in tokamak geometry is taken into account. Various wave-particle phase decorrelation models incorporated in the theory enhance its physical relevance. Preliminary numerical results show important differences from simpler approaches. (orig.)