Influence of wall impedance and self-fields on the cyclotron maser instability This paper presents a quasilinear analysis of the relativistic electron cyclotron maser instability in which the self-consistent set of equations governing the evolution of the particle distribution function and the energy spectra of unstable waves is numerically solved for parameters typical of the Earth's auroral zone plasma, taking into account both resonant and non-resonant diffusions. The results obtained show that only 0.1%0.2% of the particle energy is converted into wave energy by the loss cone instability, and also show that the saturation amplitude for the extraordinary mode increases in proportion to the ratio between electron cyclotron frequency and electron plasma frequency, in agreement with previous results obtained with numerical simulations. © 1997 American Institute of Physics. S1070-664X9704407-8