KEIO RESEARCHERS INFORMATION SYSTEM

Career 【 Display / hide 】

Career 【 Display / hide 】

• 2024.04

  -

  Present

  Keio University, Faculty of Science and Technology, Professor

• 2020.02

  -

  Present

  National Institutes for Quantum and Radiological Science and Technology, Visiting Researcher

• 2008.04

  -

  2011.03

  Japan Atomic Energy Agency, Sector of Fusion Research and Development, Postdoctoral Fellow

• 2011.04

  -

  2016.03

  Japan Atomic Energy Agency, Sector of Fusion Research and Development, Researcher

• 2016.04

  -

  2016.06

  National Institutes for Quantum and Radiological Science and Technology, Fusion Energy Research and Development Directorate, Senior Researcher

display all >>

Academic Background 【 Display / hide 】

Academic Background 【 Display / hide 】

• 1998.04

  -

  2002.03

  Keio University, Faculty of Science and Technology, Department of Applied Physics and Physico-Informatics

  University, Graduated

• 2003.04

  -

  2005.03

  Keio University, Graduate School of Science and Technology, School of Fundamental Science and Technology

  Graduate School, Completed, Master's course

• 2005.04

  -

  2008.03

  Keio University, Graduate School of Science and Technology, School of Fundamental Science and Technology

  Graduate School, Completed, Doctoral course

Academic Degrees 【 Display / hide 】

Academic Degrees 【 Display / hide 】

• Ph.D (Engineering), Keio University, Coursework, 2008.03

  Study of Flow Structure and Transport Process of Heavy Metal Impurity in Tokamak Edge Plasmas

Research Areas 【 Display / hide 】

Research Areas 【 Display / hide 】

• Energy Engineering / Fundamental plasma

• Energy Engineering / Nuclear fusion

Research Keywords 【 Display / hide 】

Research Keywords 【 Display / hide 】

• Plasma

• Computer Simulation

• Fusion

• Divertor Plasma

• Ion source plasma

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Evaluation of local erosion and deposition on the W-monoblock of JA-DEMO divertor

  Oya M., Hoshino K., Asakura N., Sakamoto Y., Ohno N., Hanada K.

  Nuclear Materials and Energy 41 2024.12

  Research paper (international conference proceedings), Joint Work, Accepted

  　View Summary

  We developed and performed a 3D Monte-Carlo simulation on local erosion and deposition in outer divertor target of JA-DEMO. The local erosion and deposition were evaluated considering the divertor plasma parameters and the roof shape of W-monoblocks. First, for local erosion simulation, the trajectories of D ions and impurity (He and Ar) ions were traced before irradiating the monoblock surface. The physical sputtering was calculated by these ions irradiation, considering their charge states, incident-energies and -angles. The highest sputtering flux was produced by multiply-charged Ar ions (Ar3+–Ar5+). The sputtering flux strongly depended on the poloidal positions along the divertor target. Although almost no erosion (sputtering) was obtained in low-temperature zone (∼1 eV), the erosion occurred in mid- (∼10 eV) and high-temperature (>10 eV) zone. Second, for local deposition simulation, the trajectories of W atoms emitted from the monoblock surface were traced. After transport (including ionization and recombination) in the plasma, W atoms and ions were deposited on the monoblock surface. The deposition occurred even on the area where plasmas did not irradiate (shadow). This was due to perpendicular diffusion to magnetic field lines, gyro-orbit effects for W ions and straight-line motion for neutral W atoms. The poloidal distribution of the deposition fluxes was similar to that of the sputtering fluxes. In low-temperature zone, no deposition flux occurred due to very low sputtering flux. The deposition flux in mid-temperature zone increased significantly and that in high-temperature zone remained high.

  • Access to Document (DOI)

• Investigation of spatial distribution characteristics of emission intensity in detachment on the divertor simulator TPDsheet-ICR

  Tonegawa A., Okada N., Miura K., Natume H., Sato K.N., Hoshino K., Hayashi Y., Masuzaki S., Yamoto S.

  Nuclear Materials and Energy 41 2024.12

  Research paper (international conference proceedings), Joint Work, Accepted

  　View Summary

  For the first time, we have revealed the spatial structure of a detached plasma with electron–ion recombination (EIR) and molecular-activated recombination (MAR) in response to changes in ion temperature (Ti) and gas pressure. This was achieved using high-density sheet plasma generated by a linear divertor simulator (TPDsheet-ICR). The parallel-plate electrodes were positioned above and below the sheet plasma (∼1019 m−3). We varied the Ti from 3 to 7 eV using ion cyclotron resonance heating and investigated the parameters of the detached plasma near the target in the divergent field region. Plasma emission intensities at Balmer series (Hα and Hγ) and Fulcher band wavelengths (610 ± 10 nm) were measured with a high-speed camera equipped with an Arbaa prism. Additionally, a Langmuir probe measured the electron density and temperature of the plasma. Our results show that as the Ti increases, EIR generated near the plasma periphery disappears, while MAR gradually forms near the plasma center during the transition from detached to attached plasma. This transition occurs because the increase in Ti in the detached plasma transfers energy from ions to electrons, raising the high-energy component of the electrons, resulting in EIR disappearance and the onset of MAR.

  • Access to Document (DOI)

• Analyses of Particle and Energy Balances using a Core-SOL-Divertor (CSD) Model for Tokamak DEMO-Reactor Studies

  YAMADA Kazuhiro, HOSHINO Kazuo, HATAYAMA Akiyoshi

  Plasma and Fusion Research (The Japan Society of Plasma Science and Nuclear Fusion Research)  19 ( 0 ) 1403034 - 1403034 2024.11

  Research paper (scientific journal), Joint Work, Accepted

  　View Summary

  <p>Understanding of key physics and engineering parameters is one of the most important issues to conduct fundamental design studies of future fusion reactors. Also, sensitivity analyses of performance by parameter surveys need to be done for optimizing a reactor. This research aims at a qualitative analysis to identify directions of design parameter optimization for fusion reactors. For this purpose, a Core-SOL-Divertor (CSD) model has been employed, because it is suitable for a wide range of parameter surveys by changing various parameters with low computational costs. This paper analyzes the particle and energy balances of the JT-60U divertor plasma by using a CSD model and reveals dependencies of the balances on design parameters of the device. In addition, the same CSD model is applied to conduct divertor plasma analyses for a future demonstration reactor (JA-DEMO). The result shows that it is possible to obtain a low temperature state of its divertor plasma as has been already reported by a two-dimensional SOL-Divertor integrated code. From these results, this paper shows that the CSD model is applicable to basic studies of directions and design concepts for future fusion reactors.</p>

  • Access to Document (DOI)
  • CiNii Research

• Recent progress of JT-60SA project toward plasma operation

  Shirai H., Takahashi K., Di Pietro E., Abate D., Abdel Maksoud W., Abe H., Aiba N., Abe T., Akimitsu M., Ayllon-Guerola J., Arai T., Artaud J.F., Asakura N., Ashikawa N., Balbinot L., Barabaschi P., Baulaigue O., Belonohy E., Belpane A., Bin W., Bombarda F., Bolzonella T., Bonne F., Bonotto M., Botija J., Buermans J., Cabrera-Pérez S., Cardella A., Carralero D., Carraro L., Cavalier J., Cavinato M., Chernyshova M., Chiba S., Clement-Lorenzo S., Cocilovo V., Coda S., Coelho R., Coffey I., Collin B., Corato V., Cucchiaro A., Czarski T., Dairaku M., Davis S., Day C., Dela Luna E., De Tommasi G., Decool P., Di Pace L., Dibon M., Disset G., D’Lsa F., Ejiri A., Endo Y., Ezumi N., Falchetto G., Fassina A., Fejoz P., Ferro A., Fietz W., Figini L., Fornal T., Frello G., Fujita T., Fukuda T., Fukui K., Fukumoto M., Funaba H., Furukawa M., Futatani S., Gabellieri L., Gaio E., Galazka K., Garcia J., Garcia-Dominguez J., Garcia-Lopez J., Garcia-Munoz M., Garzotti L., Gasparini F., Gharafi S., Giacomelli L., Ginoulhiac G., Giruzzi G., Giudicotti L., Gonzalez-Martin J., Guillén-González R., Hajnal N., Hall S., Hamada K., Hanada K., Hanada M., Hasegawa K., Hatakeyama S., Hauer V., Hayashi N., Hayashi T., Heller R., Hidalgo-Salaverri J., Higashijima S.

  Nuclear Fusion 64 ( 11 )  2024.11

  Research paper (scientific journal), Joint Work, Accepted,  ISSN  00295515

  　View Summary

  Superconducting (SC) tokamak JT-60SA plays an essential role in fusion research and development by supporting and complementing the ITER project, providing directions to the DEMO design activity and fostering next generation scientists and engineers. Since the short circuit incident at the terminal joints of equilibrium field coil #1 during the integrated commissioning (IC) in March 2021, both EU and JA implementing agencies (IAs) have examined how to ensure safe operation of JT-60SA by mitigating the risk of possible discharge occurrence inside the cryostat. Based on the experience of the global Paschen tests, the IAs have established a strategy of risk mitigation measures, which is a combination of (i) reinforcement of insulation, (ii) avoiding unnecessary voltage application to the coil systems and (iii) immediate de-energization of the coils when deteriorated vacuum conditions are detected. Thanks to the considerable efforts of the Integrated Project Team members, the IC restarted in May 2023. After confirmation of the SC state of the coil systems (TF, EF and CS), the coil energization test and the plasma operation phase 1 (OP-1) started. The first plasma was successfully achieved on 23 October 2023 with a limited value of voltage and current applied to the coils. The plasma configuration control was also confirmed with low plasma current and low auxiliary heating power conditions. Based on the IO-F4E-QST collaboration, activities of JT-60SA have been shared with the IO and provided an important lesson for ITER assembly and commissioning, and will provide an outstanding contribution to fusion research at large. After OP-1, maintenance & enhancement phase 1 (M/E-1) starts from January 2024, in which in-vessel components are installed, and heating and diagnostic systems are extensively upgraded to allow a high power heating experiment planned in OP-2. In order to make the best use of JT-60SA, a newly organized JT-60SA experiment team will refine the research plan for the future high heating power operation phase.

  • Access to Document (DOI)

• Emission of high rovibrational hydrogen molecules under detached plasma by recycling on tungsten wall

  Saito S., Nakamura H., Sawada K., Hoshino K., Kojima Y., Doi T., Kobayashi M., Hasuo M., Homma Y., Yamoto S.

  Nuclear Fusion 64 ( 12 )  2024.10

  Research paper (scientific journal), Joint Work, Accepted,  ISSN  00295515

  　View Summary

  It is well known that the rate coefficient of molecular-assisted recombination (MAR) varies by several orders of magnitude depending on the rovibrational states of the hydrogen molecules. A molecular dynamics simulation is performed to estimate the rovibrational states of recycled hydrogen molecules at the divertor in the JA-DEMO reactor under detached plasma conditions. The simulation results reveal that molecules in high rovibrational states are released even with low incident energy, which will be the dominant condition under detached plasma conditions. Molecules generated in this way can strongly affect the formation of the detached plasma via a molecular assisted-process such as MAR.

  • Access to Document (DOI)

display all >>

Papers, etc., Registered in KOARA 【 Display / hide 】

Papers, etc., Registered in KOARA 【 Display / hide 】

• Study of impurity transport in boundary plasma of fusion device

  Hoshino, Kazuo

  学事振興資金研究成果実績報告書 (慶應義塾大学)  2018

• Kinetic modeling of fusion edge plasma and dynamic characteristics of detachment plasmas

  Hoshino, Kazuo

  科学研究費補助金研究成果報告書 2017

Reviews, Commentaries, etc. 【 Display / hide 】

Reviews, Commentaries, etc. 【 Display / hide 】

• イオン源の数値シミュレーション技術の進展と応用

  星野 一生, 宮本 賢治, 畑山 明聖

  プラズマ・核融合学会誌 97   568 - 596 2021

  Article, review, commentary, editorial, etc. (scientific journal), Joint Work

  • CiNii Research

• 小特集統合コードによる磁場閉じ込め核融合プラズマシミュレーションの現状と今後の展望：　２．統合コードを構成する物理モジュール群

  村上定義，本多充，相羽信行，松山顕之，林伸彦，星野一生，藤田隆明，福山淳，横山雅之

  プラズマ・核融合学会誌 95 ( 09 ) 427 - 436 2019.09

  Article, review, commentary, editorial, etc. (scientific journal), Joint Work

• 小特集　原型炉に向けてのダイバータの研究開発課題ー現状と展望ー：　２．日本における原型炉ダイバータ概念の現状と開発課題

  朝倉伸幸、星野一生

  プラズマ・核融合学会誌 92 ( 12 ) 870 - 876 2016.12

  Article, review, commentary, editorial, etc. (scientific journal), Joint Work

• 小特集　原型炉に向けてのダイバータの研究開発課題ー現状と展望ー：3 非接触プラズマと熱・粒子処理に関するダイバータ実験研究およびモデリングの現状と研究開発課題　3.2 ダイバータモデリング研究

  星野一生

  プラズマ・核融合学会誌 92 ( 12 ) 882 - 885 2016.12

  Article, review, commentary, editorial, etc. (scientific journal), Single Work

• 小特集 DEMOに向けた直線型装置を用いた境界プラズマ、プラズマ・壁相互作用研究： １．直線型プラズマ生成装置の現状と原型炉ダイバータ設計における課題

  坂本瑞樹、大野哲靖、朝倉伸幸、星野一生

  プラズマ・核融合学会誌 90 ( 08 ) 473 - 479 2014.08

  Article, review, commentary, editorial, etc. (scientific journal), Joint Work

display all >>

Presentations 【 Display / hide 】

Presentations 【 Display / hide 】

• 直線型プラズマ装置NAGDIS-IIを用いた非接触プラズマに関する実験・モデリングの進展と今後の展開

  大野哲靖、田中宏彦、眞野綾二、上松雄太、夏目祥揮、澤田圭司、梶田信、林祐貴、石劼霖、星野一生、荒巻光利

  第15回核融合エネルギー連合講演会 (八戸) , 

  2024.06

  , 

  Poster presentation

• 炉心とSOL・ダイバータとの統合モデリングの進展

  林伸彦、矢本昌平、星野一生

  第15回核融合エネルギー連合講演会 (八戸) , 

  2024.06

  , 

  Poster presentation

• Hydrogen Recycling Model on Tungsten Materials by Machine Learning based on Molecular Dynamics Simulation

  S. Saito, M. Iida, H. Nakamura, K. Sawada, K. Hoshino, M. Kobayashi, M. Hasuo, Y. Homma, S. Yamoto

  the 26th International Conference on Plasma Surface Interaction in Controlled Fusion Devices (Marseille, France) , 

  2024.05

  , 

  Poster presentation

• Simulation studies of power and Helium exhaust in detach divertor and impurity transport for JA-DEMO divertor

  N. Asakura, K. Hoshino, Y. Homma, T. Yamamoto, Y. Sakamoto

  the 26th International Conference on Plasma Surface Interaction in Controlled Fusion Devices (Marseille, France) , 

  2024.05

  , 

  Poster presentation

• Numerical Investigation of Hydrogen Molecule Release in High Rovibrational States from Tungsten Walls

  H. Nakamura, S. Saito, K. Sawada, K. Hoshino, Y. Kojima, T. Doi, M. Kobayashi, M. Hasuo, Y. Homma, S. Yamoto

  the 26th International Conference on Plasma Surface Interaction in Controlled Fusion Devices (Marseille, France) , 

  2024.05

  , 

  Poster presentation

display all >>

Research Projects of Competitive Funds, etc. 【 Display / hide 】

Research Projects of Competitive Funds, etc. 【 Display / hide 】

• Understanding energy and momentum losses associated with the generation and transport of excited particles and control of detached recombining plasma

  2024.04

  -

  2028.03

  Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Coinvestigator(s)

  　View Summary

  磁場閉じ込めプラズマ核融合炉の実現のためには，炉心プラズマから周辺領域に流出する膨大な粒子流および熱流を制御し，直接プラズマと接触するプラズマ対向材(ダイバータ板)の損傷を低減することが最重要課題の一つとなっている。熱負荷低減法として，非接触再結合プラズマ（Detached Recombining Plasmas）形成による熱流制御法の確立の重要性が指摘されている。本研究では，直線型高密道プラズマ発生装置を用いた実験と流体コード，中性粒子輸送コードをカップリングした統合コードによる解析により，非接触再結合プラズマの生成機構と制御手法を確立し，核融合発電の早期実現に資する。

• ダイバータ配位プラズマの境界層におけるプラズマ流と不純物輸送へのドリフトの効果

  2022.04

  -

  2026.03

  Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Coinvestigator(s)

  　View Summary

  内部コイルを用いてダイバータ配位の環状プラズマを生成し、その境界層におけるプラズマ流や不純物イオンの流速などを詳細に計測する。三角形度などプラズマ断面形状を様々に変えた実験を実施し、ダイバータプラズマシミュレーションコードの結果と比較する。これにより、プラズマ流に対するイオンドリフトの効果を明らかにするとともに実験的な裏付けのある不純物輸送モデルを提案する。

• Elucidation and control of the physical and chemical mechanisms governing the spatio-temporal structure of detached recombining plasmas

  2020.04

  -

  2024.03

  Nagoya University, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Research grant, Coinvestigator(s)

  　View Summary

  プラズマプロセッシングや核融合研究において重要な課題となっている気相中で消えるプラズマの物性を明らかにする。電子・イオン再結合（三体再結合，放射再結合）が主要な過程となる再結合プラズマ中の非熱平衡性，電位構造に関連した熱・粒子輸送過程を，直線型高密度プラズマ発生装置を用いた基礎実験とシミュレーションとの相補的な研究により明らかにする。また，振動励起水素分子により駆動される再結合（分子駆動再結合）プラズマ生成に関して，固体壁で生成される振動・回転励起水素分子の影響と同位体効果を明らかにする。さらに，再結合プラズマのパルス応答を高時間分解で調べ，時空間変化を決定する物理・化学過程を明らかにする。

• 重水素負イオン源における同位体効果の物理メカニズムの理論的解明

  2019.04

  -

  2022.03

  Naruto University of Education, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Coinvestigator(s)

  　View Summary

  本研究は重水素負イオン源について、運動論的粒子モデルに基づく数値計算シミュレーションにより、負イオン源のドライバー領域から引出・加速部までを総括的にモデリングし、「研究の目的」に挙げた同位体効果と呼ばれる水素の場合と異なる物理特性のメカニズムを解明することが目的である。そして得られた知見により、核融合や医療用加速器等において、研究開発が進められている重水素負イオン源の実現に貢献する。

• 運動論的統合モデリングによる非接触ダイバータプラズマの動的応答特性の解明

  2019.04

  -

  2022.03

  Keio University, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), No Setting, Principal investigator

  　View Summary

  核融合原型炉に向けた最重要課題であるダイバータにかかる熱・粒子負荷の低減には、非接触ダイバータプラズマの形成と制御が必須である。本研究課題では、この非接触ダイバータプラズマの物理機構と動的応答特性の解明を目的とする。まず、プラズマPIC(Particle in Cell)モデルと先進的中性粒子輸送コードを用いて、ダイバータプラズマの基本的な動特性の理解を進める。その後、これらのモデルを結合した運動論的統合シミュレーションコードを開発する。開発した統合コードを用いて、非接触ダイバータプラズマの動的応答特性について総合的な理解を進め、その物理機構を明らかにする。

display all >>

Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• SPECIAL TOPICS IN APPLIED PHYSICS AND PHYSICO-INFORMATICS

  2024

• SCIENCE OF ATOMIC ENERGY

  2024

• PRESENTATION TECHNIQUE

  2024

• PLASMA PHYSICS

  2024

• PLASMA PHYSICS

  2024

display all >>

Memberships in Academic Societies 【 Display / hide 】

Memberships in Academic Societies 【 Display / hide 】

• Japan Society for Simulation Technology, 

  2022.07

  -

  Present

• The Japan Society of Plasma Science and Nuclear Fusion Research, 

  2001.08

  -

  Present

Committee Experiences 【 Display / hide 】

Committee Experiences 【 Display / hide 】

• 2021.09

  -

  Present

  Member of the International Scientific Committee of Plasma Edge Theory in Fusion Devices

• 2019.12

  -

  Present

  核融合エネルギーフォーラム専門委員

• 2019.07

  -

  Present

  炉心プラズマ共同企画委員会　理論シミュレーション専門部会　専門委員, 量子科学技術研究開発機構

• 2017.07

  -

  2019.06

  編集委員, プラズマ・核融合学会