Millimeter wave generation by relativistic electron beams

We are studying various wave-plasma interaction processes towards the understanding of the collective physics of plasmas. The processes include the mechanisms leading to the generation of millimeter waves by relativistic electron beams (electron cyclotron maser instability) and the mechanisms providing channels for anomalous absorption of electromagnetic waves (electron cyclotron resonance heating and parametric instabilities). A single nonlinear equation which describes the temporal evolution of the field amplitude of the electron cyclotron maser instability has been derived self-consistently. Three adiabatic invariants of the electron motion under the electon cyclotron resonance heating by three differently polarized heater: (1) ordinary mode; (2) extraordinary mode; and (3) electrostatic mode are derived. Wave plasma interaction leading to various parametric instabilities in the ionsphere has also been studied.