Simulation studies of parametric decay processes associated with ionospheric stimulated radiation


  • A. A. Hussein,

  • W. A. Scales


Parametric instability processes are thought to produce stimulated electromagnetic emissions during ionospheric heating experiments. The phenomenon is primarily attributed to plasma turbulence excited by the high-frequency heater in the altitude region where the pump frequency ω0 is near the plasma upper hybrid frequency ωuh. In this study, parametric instability processes thought to produce ionospheric stimulated radiation are studied using electrostatic particle-in-cell simulation models. The emphasis in this work will be to consider the excitation and interactions between electrostatic waves generated by the pump wave. The simulation plasma is driven with a uniform oscillating electric field directed nearly perpendicular to the background geomagnetic field B to consider interactions when ωuh is near electron cyclotron harmonics nΩce. The pump frequency and amplitude are varied to consider the effects on the simulation electric field power spectrum. Also, the effect of varying the electron to ion temperature ratio Te/Ti is discussed and evaluated. The simulation results show richly structured sidebands upshifted and downshifted above and below the pump frequency, which are attributed to parametric instability processes. The relationship between the simulation results, the theoretical models, and the experimental spectrum are discussed.