Effects of Lower-Hybrid Heating on the Hot Electrons in an Electron-Cyclotron-Resonance Plasma

Experiments were performed on an electron cyclotron resonance plasma in a dc magnetic mirror to determine the effects of lower hybrid resonance radiation on the anisotropy of the plasma. It was found that the anisotropy of the plasma hot electrons decreased, the flux of hot electrons escaping through the mirror throats decreased and the midplane wall bremsstrahlung rate slightly increased as lower hybrid resonance power was increased. This is explained by observing that cold plasma, expelled by the lower hybrid radiation, decreases the number of scattering centers in the midplane, which results in a deeper diamagnetic well for the hot electrons.