Experimental study of hot electrons in LECR2M plasma.

In order to investigate the hot electron component in electron cyclotron resonance (ECR) plasmas, the volume bremsstrahlung spectra in the x-ray photon energy range were measured with a high-purity germanium detector on Lanzhou ECR Ion Source No. 2 Modified (LECR2M). A collimation system similar to Bernhardi's was used to focus at the central part of the plasma. The ion source was operated under various source conditions with argon; sometimes oxygen was added to enhance high charge state ion beam intensities. The spectral temperature of hot electrons T-spe was derived from the measured bremsstrahlung spectra. The evolution of the deduced temperature of hot electrons T-spe with the ion source parameters, such as the rf frequency, power, and the magnetic confinement configuration, was investigated. (c) 2008 American Institute of Physics.