The diagnosis is based on the theories of the electron cyclotron maser instability and cyclotron resonance absorption.

The output frequency of ICL is obtained from the resonance condition, and the comparison is carrying out among ICL, Cyclotron Auto resonance Maser (CARM) and conventional Free Electron Laser (FEL).

This paper discusses non-local magnetic trapping resonance effects of weakly relativistic electron on cyclotron maser in the magnetic mirrors.