Development of Negative-Ion Based NBI System for JT-60.

Kuriyama, M.; Akino, N.; Ebisawa, N.; Grisham, L.; LIQUEN, Hu; Honda, Akira; Itoh, Takaò; Kawai, M.; Kazawa, M.; Mogaki, K.; Ohara, Y.; Ohga, T.; Ohmori, K.; Okumura, Y.; Oohara, H.; Usui, K.; Watanabe, K.

doi:10.3327/jnst.35.739

Cited by 19 publications

(10 citation statements)

References 9 publications

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“…Hydrogen negative ion (H − ) source used cesium (Cs) vapor, which is effective to improve H − current density, have been developed in many research facilities [1][2][3]. We have adopted six large H − sources used arc discharge for the Large Helical Device (LHD) experiment, and these are successfully operated.…”

Section: Introductionmentioning

confidence: 99%

Observation of Hydrogen and Cesium Spectra in a Negative Ion Source for a Neutral Beam Injector using a Multi-Channel Spectrometer

Ikeda

Fantz

Nagaoka

et al. 2007

Plasma and Fusion Research

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Effective production of hydrogen negative ions (H − ) is one of the important issues in high power neutral beam injection (NBI) for fusion experimental devices. Cesium (Cs) vapor is seeded in the H − sources to enhance the H − production rate, which depends strongly on the amount of Cs inside the source. On the other hand, oxygen and water attenuate the production rate. In order to investigate the states of those species inside ion source, we have installed two multi-channel spectrometer systems with different spectral resolution. Hydrogen emissions, Cs emissions and oxygen emission are clearly observed with the time resolution of several handled milliseconds. Most of evaporated Cs atoms ionize in arc discharge plasma, and the emission increases strongly due to the ion back streaming with beam extraction. Oxygen neutral emission increases at the beginning of the beam conditioning, and its evaporation depends on the condition of the grid system.

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Section: Introductionmentioning

confidence: 99%

Observation of Hydrogen and Cesium Spectra in a Negative Ion Source for a Neutral Beam Injector using a Multi-Channel Spectrometer

Ikeda

Fantz

Nagaoka

et al. 2007

Plasma and Fusion Research

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“…1,2 Negative-ion based NBI systems equipped with cesium-fed volume-production type hydrogen ion sources 3 have already worked since 1998 in the large helical device ͑LHD͒. 4 Injection of a high power beam of 10 MW or a long pulse beam of 110 s is carried out.…”

Section: Introductionmentioning

confidence: 99%

Control of negative ion beam uniformity by using multipower supplies for arc discharge

Ikeda

Takeiri

Kaneko

et al. 2004

Review of Scientific Instruments

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Multipower supplies for the arc discharge are installed to improve beam uniformity of a large size of the neutral beam injection system in the large helical device ͑LHD͒. The plasma tends to shift on the upper side of the arc chamber when the same arc voltage is applied to all filaments. The arc discharge current distribution becomes uniform as a consequence of the individual voltage control, but about 20 V difference of the arc voltage between the top and bottom circuits is required. We have estimated the beam profile from each acceleration grid by comparing the calculation and measurement of the beam profile of H␣ and calorimeter. The uniformity of arc discharge has been improved in most regions without the discharge adjustment by a horizontal filament connection. The controllability of the arc discharge distribution of the horizontal filament connection is better than that of the vertical filament connection. The efficiency of the beam production is improved by about 10% in the case of the horizontal filament connection. As a result 3.7 MW of the beam injection has been achieved in the LHD 6th experimental campaign in 2003.

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“…The first application of negative ions in MFE was on the JT-60U tokamak [1] at Naka, Japan. This system has now injected neutral beam power levels of 5.8 megawatts at 400 keV for 0.9 seconds using deuterium, and 2.6 megawatts at 355 keV for 10 seconds using hydrogen.…”

Section: Mfe Negative Ion Beamsmentioning

confidence: 99%

Progress of Negative Ions in Fusion Research

Grisham¹

2003

AIP Conference Proceedings

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Optimization of negative ion sources for a heavy-ion-beam probe Rev. Sci. Instrum. 77, 03A537 (2006); 10.1063/1.2170094 Efficient negative-ion sources for radioactive ion beam applications (abstract) Rev. Sci. Instrum. 73, 796 (2002);Abstract. Negative ion beams are assuming increasing significance in the field of controlled fusion research. The first generation of large high current negative ion sources has now operated successfully on the JT-60U tokamak for some years, producing negative ions of hydrogen or deuterium at energies up to 400 keV for conversion to several megawatts of neutrals which are used for plasma heating and current drive. We report an unexpected intensification phenomenon, and some of the improvements made or planned. In the realm of inertial confinement fusion, interest has grown in the use of heavy negative ion driver beams formed from halogens such as bromine, iodine, or chlorine. We discuss the advantages of negative ions as heavy ion fusion drivers, and assess the technical feasibility of a halogen negative beam system. We also discuss the potential for photodetaching the negative ions to produce atomically neutral beams and reduce beam space charge effects within the target chamber

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Development of Negative-Ion Based NBI System for JT-60.

Cited by 19 publications

References 9 publications

Observation of Hydrogen and Cesium Spectra in a Negative Ion Source for a Neutral Beam Injector using a Multi-Channel Spectrometer

Observation of Hydrogen and Cesium Spectra in a Negative Ion Source for a Neutral Beam Injector using a Multi-Channel Spectrometer

Control of negative ion beam uniformity by using multipower supplies for arc discharge

Progress of Negative Ions in Fusion Research

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