Negative Absorption Due to Coulomb Scattering of an Electron Stream

Abstract

Radio-frequency electrical conductivities are calculated with electrons drifting through an ion cloud under an externally applied static electric field. The stationary velocity distribution of electrons is taken to be a displaced Maxwellian. Then, if the drift velocity is larger than 0.8 times the electron velocity spread, the real part of the electrical conductivity becomes negative at frequencies much higher than the mean-collision frequency.