In this paper we report surface scattering experiments on graphite in an attempt to investigate fundamental charge exchange processes on divertor surfaces in plasma devices. A remarkably high H- ion fraction (10-20%) as a function of outgoing angle of the scattered particles is found during scattering of positive hydrogenous ions (H+, H2+ and H3+). These results cannot be explained with conventional theories of charge transfer.

K. Prelec

Tsumori, K, Koppers, W.R, Heeren, R.M.A, Kadodwala, M.F, Kleyn, A.W, & Beijersbergen, J.H.M. (1996). Negative hydrogen production at a graphite surface. In K Prelec (Ed.), Production and Neutralization of Negative Ions and Beams : 7th Int. Symp. , Production and Application of Light Negative Ions : 6th European Workshop, A Joint Meeting, Upton, NY October 1995 (pp. 36–40). AIP.