Diagnostics in a single element of a matrix source of negative hydrogen ions.

A small radius discharge in hydrogen inductively driven by a planar coil is studied experimentally regarding development of a matrix source of negative hydrogen ions: a matrix of small radius discharges, each of them completed with a magnetic filter and a single aperture extraction device. Probe and laser photodetachment diagnostics are the methods employed. Results for the axial structure of the discharge show the influence of the absorbed rf power, of the magnetic filter (and its position), and of the bias applied to the first electrode of the extraction device on the spatial distribution of the plasma parameters and on the discharge modes.