Negative Ion Production in High Electron Temperature Plasmas

Tobari, H.; Seki, T.; Takado, N.; Hanada, M.; Inoue, Takashi; Kashiwagi, M.; Hatayama, A.; Sakamoto, K.

doi:10.1585/pfr.2.022

Cited by 12 publications

(7 citation statements)

References 7 publications

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“…The origin of spatial non-uniformity in multi-cusp arc-discharge sources has been extensively studied by using the QST (National Institute for Quantum and Radiological Science and Technology) 10A source (see figure 7). Not only the experimental studies [21,74], but also the modeling studies [25][26][27][28][29][30] and their comparison of the experimental results have been done so far.…”

Section: Modeling Of Qst 10a Source [25-30]mentioning

confidence: 99%

Present status of numerical modeling of hydrogen negative ion source plasmas and its comparison with experiments: Japanese activities and their collaboration with experimental groups

et al. 2018

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The present status of kinetic modeling of particle dynamics in hydrogen negative ion (H − ) source plasmas and their comparisons with experiments are reviewed and discussed with some new results. The main focus is placed on the following topics, which are important for the research and development of H − sources for intense and high-quality H − ion beams: (i) effects of non-equilibrium features of electron energy distribution function on volume and surface H − production, (ii) the origin of the spatial non-uniformity in giant multi-cusp arc-discharge H − sources, (iii) capacitive to inductive (E to H) mode transition in radio frequency-inductively coupled plasma H − sources and (iv) extraction physics of H − ions and beam optics, especially the present understanding of the meniscus formation in strongly electronegative plasmas (so-called ion-ion plasmas) and its effect on beam optics. For these topics, mainly Japanese modeling activities, and their domestic and international collaborations with experimental studies, are introduced with some examples showing how models have been improved and to what extent the modeling studies can presently contribute to improving the source performance. Close collaboration between experimental and modeling activities is indispensable for the validation/improvement of the modeling and its contribution to the source design/development. chamber wall (anode) and filaments (cathode). In the latter sources, the RF-electromagnetic field is used to generate and heat plasmas.In this review, we mainly focus on the modeling studies, especially the modeling study of H − source plasmas using kinetic approaches, such as the test particle Monte-Carlo model [14] and particle in cell (PIC) model [14,15], which has been reviewed in [16]. Here, we extend it with some new results. Close collaboration between the experimental and modeling study is very important as it can improve our basic understanding of source plasmas. Various examples of the model validation will be shown through comparisons with experiments and also how modeling studies contribute to the improvement of source performances.As for the multi-cusp arc-discharge source, we will first show a systematic study to help us understand the role of the EEDF on the H − VP in section 2.2. The study has been carried out for a compact multi-cusp arcdischarge source (SHI H − source: Sumitomo Heavy Industry H − source [17,18]) for medical application such as boron neutron capture therapy and the radioisotope production for molecular imaging technology.The SHI H − source is a typical tandem type H − source [19]. In such a tandem type volume sources, the plasma source volume is divided into two regions by the transverse magnetic field (the so-called magnetic filter filed: MF-field) to control the EEDFs and to promote the two step H − VP reactions explained above. Namely, the source volume consists of two regions: (1) the 'driver region' where the electron energy is high and the EV process is promoted, and (2) the 'extraction region' where the electr...

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Section: Modeling Of Qst 10a Source [25-30]mentioning

confidence: 99%

Present status of numerical modeling of hydrogen negative ion source plasmas and its comparison with experiments: Japanese activities and their collaboration with experimental groups

et al. 2018

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“…The local enhancement of the H ¼ atom production due to the high electron temperature and the resulting non-uniformity of the H ¼ atom flux to the plasma grid (PG) are possible origins of the H ion beam non-uniformity observed in the JAEA 10 ampere negative ion source. Based on this, a tent filter concept with the proper setting of filament location was proposed which significantly improved the H ion beam uniformity [101,108].…”

Section: H Transport Modelingmentioning

confidence: 99%

Particle in Cell Simulation of Low Temperature Laboratory Plasmas

Matyash

Schneider

Taccogna

et al. 2007

Contrib. Plasma Phys.

107

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Several applications of PIC simulations for understanding basic physics phenomena in low-temperature plasmas are presented: capacitive radiofrequency discharges in Oxygen, dusty plasmas and negative ion sources for heating of fusion plasmas. The analysis of these systems based on their microscopic properties as accessible with PIC gives improved insight into their complex behavior. These studies are results of joint efforts over about one decade

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“…Based on these basic understandings on the origin of the H − ion beam nonuniformity, a tent filter concept with the proper setting of filament location was proposed to improve the H − ion beam uniformity and significant improvement in the H − ion beam uniformity has been achieved up to now. 4,15 …”

Section: B Origin Of H − Beam Nonuniformitymentioning

confidence: 99%

Progress in modeling and numerical simulation of negative hydrogen ion sources (invited)

Hatayama

2008

Review of Scientific Instruments

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Recent progress in numerical modeling of H(-) ion sources has been reviewed. The following two topics are mainly the focus: (1) the origin of the nonuniformity of H(-) production and H(-) beam in large H(-) sources and (2) extraction physics, especially the role of the "weak" transverse magnetic field on H(-) extraction. The present understanding of the origin of H(-) beam nonuniformity is reviewed and discussed with the results by a series of Monte Carlo transport modeling of electrons, neutrals, and H(-) ions. Also, the physical mechanism of the large enhancement of H(-) extraction due to the weak transverse magnetic field is discussed with the particle in cell modeling. In addition, some new results on the effect of surface H(-) production on the electric potential structure near the extraction aperture are presented and discussed.

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Negative Ion Production in High Electron Temperature Plasmas

Cited by 12 publications

References 7 publications

Present status of numerical modeling of hydrogen negative ion source plasmas and its comparison with experiments: Japanese activities and their collaboration with experimental groups

Present status of numerical modeling of hydrogen negative ion source plasmas and its comparison with experiments: Japanese activities and their collaboration with experimental groups

Particle in Cell Simulation of Low Temperature Laboratory Plasmas

Progress in modeling and numerical simulation of negative hydrogen ion sources (invited)

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