The effect of trapped electrons on the wave-induced current

The wave-induced current in a toroidal magnetic field is computed by use of an adjoint drift-kinetic equation for electrons. The inverse aspect ratio of the toroidal device is assumed to be small and the lowest-order terms of this ratio are retained. As the wave-absorption mechanism, the electron cyclotron damping and the electron Landau damping are considered. It is found that the induced current decreases considerably by the effect of the trapped electrons when the phase velocity of the plasma wave is low. (author)