Abstract
A new approach to enhance the production of negative ions in low-pressure hydrogen and deuterium discharges is described. The procedure, which requires on-off modulation of the discharge current, is applied to a conventional magnetic multicusp or ‘‘bucket’’ volume negative-ion source. The extracted current from a 15-A discharge at a filling pressure of 2.4 mTorr is increased from 0.5 to 2.0 mA/ by discharge-current modulation at 10 kHz and 23% duty cycle. The beam current is not significantly modulated (<5%). The extracted electron current density and average discharge current are reduced by over a factor of 4. The work is relevant to production of beams for neutral-beam injectors.
- Received 22 March 1991
DOI:https://doi.org/10.1103/PhysRevLett.67.449
©1991 American Physical Society