Fusion Science and Technology / Volume 59 / Number 1T / January 2011 / Pages 271-273
Unlike tokamaks, where the neutral beam shine through is rarely an issue, open magnetic systems with neutral beam injection oftentimes suffer from incomplete beam capture, which necessitates the handling of the shine through power load and beam particle recycling. The cathodic arc gettering, which provides high evaporation rate coupled with a fast time response, is a powerful and versatile technique for depositing clean getter films in vacuum. A compact neutral beam dump utilizing the titanium arc gettering was developed for a field-reversed configuration plasma sustained by 1 MW, 20–40 keV neutral hydrogen beams. The beam dump is capable of handling large, pulsed gas loads, has a high sorption capacity, and is robust and reliable. The beam recycling coefficient, measured under the beam particle flux density of 5 × 1017 H/(cm2s) sustained for 3–10 ms, is ~0.7. The use of the beam dump allows to reduce the recycling of the shine through neutral beam by factor of 3–5, as well as to improve the vacuum conditions in the machine.