Observations are reported of electromagnetic emissions at frequencies above the electron gyrofrequency in a mirror-confined electron cyclotron resonance plasma. These emissions are interpreted as the excitation of the fast extraordinary wave at the fundamental harmonic of the electron gyrofrequency, similar to the excitation of the auroral kilometric radiation (AKR) of the Earth. The paper proposes a method for studying the temporal characteristics of physical processes occurring in the auroral electron acceleration region, which is applied to the AKR measurements onboard INTERBALL-2 spacecraft and adopted to the measurements of laboratory plasma emissions. The joint data analysis of satellite measurements and the results of laboratory experiments showed similarities in the cyclotron instability development.