A one dimensional volume ion source model

With projects such as NET and ITER demanding high energy neutral beams for injection to provide current drive and possibly plasma heating, the low neutralisation efficiency of D+ ions has resulted in the need to develop furhter an effective D- ion source. Of the two main categories of ion source, surface plasma sources and volume ion sources, volume ion sources with magnetic filters are at present favoured for use in neutral injection systems. The construction of a computer model of such a discharge should enhance the understanding of the processes involved, and so enable experimentalists to optimise the source construction and operation. Previous attempts at ion source modelling have been described by Glasser and Smith along with their own time dependent model. Although the projects mentioned above require deuterium as their fuel the model described here will be based on hydrogen. (author) 5 refs., 6 figs