Generation of multiply-charged metal ions in vacuum arc plasmas

The status of experimental research aimed at enhancing the ion charge states in vacuum are plasmas is reviewed. Strong magnetic fields, high-current arc "spikes," and intense electron beams have been used, separately, to increase the metal ion charge states produced. For each method, systematic measurements of ion charge state distributions were made. Each method has its advantages and disadvantages and each method does result in an increase in the mean ion charge state by up to a factor of 2.4, in the work carried out to-date. The last method, use of An added intense electron beam for enhanced ion stripping, is the most effective and work in this direction is being pursued further