INVESTIGATION OF HOT-ELECTRONS IN ELECTRON-CYCLOTRON-RESONANCE ION SOURCES

The hot electrons in the plasma of an electron-cyclotron-resonance ion source are investigated by three passive diagnostics: bremsstrahlung, electron cyclotron emission, and diamagnetism. For this type of plasm a the feasibility of the second diagnostic is an innovative developmen t, as is the simultaneous use of two independent plasma diagnostics fo r either steady-state or transient experiments. In the steady-state ex periments the bremsstrahlung and the electron cyclotron emission are i nterpreted by comparing the experimental spectra with simulated spectr a calculated for the first time from a non-Maxwellian electron distrib ution. The ''perpendicular temperatures'' obtained by the two diagnost ics are in good agreement. In the transient experiments the electron c yclotron emission and the diamagnetic signals are recorded to study th e electron density and the electron lifetime. All these experiments pe rformed using the Minimafios ion source working at 18 GHz with oxygen gas demonstrate trends and saturation effects when the gas injection p ressure and the radio-frequency power are varied.