Open problems in the physics of volume H/sup -//D/sup -/ sources

Old and new problems in the physics of magnetic multipole sources for the production of negative H/sup -//D/sup -/ ions are presented and discussed. We emphasize particularly, in this kind of plasmas, both the vibrational and electron nonequilibrium energy distributions, the role of Rydberg states in enhancing the negative ion production, the production of vibrationally excited states by atomic recombination on surfaces through different mechanisms, and the enhancement of negative ion concentrations in pulsed discharges.