Synchrotron radiation in the presence of a perfect cylindrical mirror

Exact solutions are given for the Maxwell equations driven by a gyrating ultrarelativistic electron in the presence of a reflecting cylindrical boundary. The axis of the electron's circular trajectory and the axis of the surrounding cylinder are supposed to coincide. It is found that, at certain values of the ratio of the cylinder's and the trajectory's radii, the field amplitudes diverge as functions of time. The physical reason for this is the constructive interference between the radiation actually emitted and the radiation emitted earlier and (by reflection) getting back to the actual position of the electron. (author) 8 refs.; 1 fig