Negative halogen ions for fusion application
Over the past quarter century, advances in hydrogen negative-ion sources have extended the usable range of hydrogen-isotope neutral beams to energies suitable for large magnetic confinement fusion devices. Recently negative halogen ions have been proposed as an alternative to positive ions for heavy-ion fusion drivers in inertial confinement fusion, because electron accumulation would be prevented in negative-ion beams, and if desired, the beams could be photodetached to neutrals. This article reports an experiment comparing the current density and beam emittance of Cl+ and Cl- extracted from substantially ion-ion plasmas with that of Ar+ extracted from an ordinary electron-ion plasma, all using the same source, extractor, and emittance scanner. At similar discharge conditions, the Cl- current was typically 85 percent-90 percent of the positive chlorine current, with an e-/Cl- ratio as low as 7 without grid magnets. The Cl- current was as much as 76 percent of the Ar+ current from a discharge with the same rf drive. The minimum normalized beam emittance and inferred ion temperatures of Cl+, Cl-, and Ar+ were similar, so the current density and optical quality of Cl-appear as suitable for heavy-ion fusion applications as a positive noble gas ion of similar mass. Since F, I, and Br should all behave similarly in an ion source, they should also be suitable as driver beams.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Fusion EnergySciences, Princeton Plasma Physics Laboratory, Lawrence LivermoreNational Laboratory
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 898566
- Report Number(s):
- LBNL--61290; HIFAN 1469; BnR: AT5015031
- Journal Information:
- Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Vol. 77; ISSN 0034-6748; ISSN RSINAK
- Country of Publication:
- United States
- Language:
- English
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Negative Halogen Ions for Fusion Applications
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