Generation of Electron Cyclotron Microwave Emissions in a Mirror Discharge

We report observations of electromagnetic emissions at electron cyclotron harmonics in a mirror-confined electron cyclotron resonance (ECR) plasma. The present research has achieved a new understanding of electron cyclotron instabilities by comparing measurements of emissions from a well-diagnosed laboratory plasma, with the predictions of analytical theory supported by Vlasov simulations. The presence of multi-component electron distribution functions involving a warm and ring-distributed 1 200-400 eV mirror-confined population of electrons and a much colder 1 eV component lead to electrostatic electron cyclotron instabilities and results in microwave emissions. This results have relevance many areas where electron cyclotron instabilities are of fundamental importance, including astrophysical plasmas 2 , near-Earth solar-terrestrial plasmas 3 , laboratory tokamak and stellarator fusion plasmas and electron cyclotron resonance sources.