Multiple discharge channels in a cascaded arc to produce large diameter plasma beams

A new cascaded arc containing three separate discharge channels at 15 mm distance from each other was constructed to produce intense and wide hydrogen plasma beams and first tests were carried out at Pilot-PSI. Current and voltage measurements as well as calorimetry on the cooling water of the source demonstrated that these channels operated independently. Thomson scattering measurements showed that, depending on the nozzle geometry, the three outputs merge to one beam if the source is operated at argon in magnetic fields up to 1.6T densities. In hydrogen operation, the individual outputs did not merge or interact. Also a first test was performed in argon on the use of a remote ring anode to induce beam mixing due to rotation driven by cross-B currents. (C) 2009 Elsevier B.V. All rights reserved.