Some plasma aspects and plasma diagnostics of ion sources (invited)
REVIEW OF SCIENTIFIC INSTRUMENTS 79(2, Part 2), volume 79, FEB 2008, 12th International Conference on Ion Sources, Jeju Isl, SOUTH KOREA, AUG 26-31, 2007
We consider plasma properties in the most advanced type of plasma ion sources, electron cyclotron resonance ion sources for highly charged ions. Depending on the operation conditions the plasma in these sources may be highly ionized, which completely changes its transport properties. The most striking difference to weakly ionized plasma is that diffusion will become intrinsically ambipolar. We further discuss means of plasma diagnostics. As noninvasive diagnostic methods we will discuss analysis of the ion beam, optical spectroscopy, and measurement of the x-ray bremsstrahlung continuum. From beam analysis and optical spectroscopy one may deduce ion densities, and electron densities and distribution functions as a mean over the line of sight along the axis (optical spectroscopy) or at the plasma edge (ion beam). From x-ray spectra one obtains information about the population of highly energetic electrons and the energy transfer from the driving electromagnetic waves to the plasma-basic data for plasma modeling. (C) 2008 American Institute of Physics.