On the generation of auroral radio emissions at harmonics of the lower ionospheric electron cyclotron frequency:X,OandZmode maser calculations

摘要: Electron cyclotron maser emission has been suggested as a possible explanation of ground-based observations auroral radio waves at twice and three times the lower ionospheric electron frequency (2ƒce 3ƒce). Preliminary theoretical work concluded that direct excitation first second harmonics free space extraordinary mode (X2 X3) could exceed collisional damping rates, although growth rates were low. Recently, however, indicate these emissions are predominantly O polarized. Therefore reassessment an mechanism is necessary. In this paper, kinetic instability calculations extended to include trapped Z for varying thermal energies potential drops within context realistic distribution model. It found when local upper hybrid in close vicinity 2ƒce or 3ƒce, harmonic (Z2 Z3) rate shown be exceedingly high. This finding suggests indirect involves linear nonlinear conversion excited into ordinary (O) mechanism.