Characteristics of cesium-free negative hydrogen/deuterium ion source by sheet plasma.

• We have designed the magnetized-sheet plasma. • The negative ions produce by volume production without Cs seeding. • The negative hydrogen /deuterium ions are successfully extracted. • This study clarified the basic characteristics of the developed system. The use of negative ion sources without Cs seeding is desired in neutral beam injectors of fusion experiments. We have designed a magnetized-sheet plasma that produces negative ions by volume production without Cs seeding. The developed system was experimentally tested on steady-state hydrogen and deuterium plasmas. The negative hydrogen ion beam was extracted by a two-grid extraction system located at the periphery of the sheet plasma. The negative hydrogen/deuterium ions were successfully extracted from the sheet plasma. The current densities of the ion beams increased with increasing discharge current. At an extraction voltage of 7 kV and a discharge current of 80 A, the approximate current densities of the negative hydrogen and deuterium ion beams were 3.8 and 1.2 mA/cm2, respectively. [ABSTRACT FROM AUTHOR]