Abstract
The feasibility of heating tandem-mirror devices with microwaves near the electron cyclotron frequency or its harmonic is examined. Ray-tracing calculations are performed to find the optimal angle of wave launching for maximal absorption. It is found that the mirror plugs of present-day tandem-mirror devices can be heated effectively via the extraordinary mode, and that in the next generation of devices both the ordinary and the extraordinary mode of propagation can be used. Presently available gyrotrons can be used as sources of microwave energy in these experiments.