1. I. G. Brown, Rev. Sci. Instrum. (to be published), and references therein.
2. See, for instance, E. D. Donets, inThe Physics and Technology of Ion Sources, edited by I. G. Brown (Wiley, New York, 1989), Chap. 12.
3. P. Spädtke, I. G. Brown, and P. Fojas, these proceedings.
4. G. A. Farrall, inVacuum Arcs, Theory and Application, edited by J. M. Lafferty (Wiley, New York, 1980), Chap. 6.2.
5. H. C. Miller, Proceedings of the XIV Int. Symposium on Discharges and Electrical Insulation in Vacuum, Santa Fe, CA, 1990 (unpublished), p. 140.