The electron cyclotron absorption and emission in the presence of a small population of electrons in motion relative to an isotropic Maxwellian bulk are investigated for the case for which the distribution of the streaming electrons is Maxwellian in the co-moving frame. The dielectric tensor accounting for the complete relativistic cyclotron resonance condition is used and the contribution from the streaming electrons to the absorption as well as to the emission is evaluated by Lorentz-transforming from the co-moving to the laboratory frame the dielectric tensor and Kirchhoff's law. A detailed numerical study of the profile of both the absorption and radiation temperature of the ordinary as well as the extraordinary mode around the first harmonic is performed and the corresponding scaling with respect to the relevant parameters is discussed.
Electron cyclotron emission during electron cyclotron heating in tokamaks