KEIO RESEARCHERS INFORMATION SYSTEM

Career 【 Display / hide 】

Career 【 Display / hide 】

• 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

• 2016.07

  -

  2018.03

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

• 2018.04

  -

  Present

  Keio University, Faculty of Science and Technology, Associate Professor

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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 】

• 博士（工学）, Keio University, Coursework

  トカマクにおける境界層プラズマ流の構造と重金属不純物輸送に関する研究

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 】

• Effect of Surface Produced H^-Ion on the Plasma Meniscus in Negative Hydrogen Ion Sources

  HAYASHI Katsuya, HOSHINO Kazuo, HATAYAMA Akiyoshi, MIYAMOTO Kenji, LETTRY Jacques

  Plasma and Fusion Research （The Japan Society of Plasma Science and Nuclear Fusion Research)  18 （ 0 ） 1401008 - 1401008 2023.03

  Research paper (scientific journal), Joint Work, Accepted

  　View Summary

  <p>To extract intense ion beams with good beam optics from ion sources, controlling the distance <i>d</i>_effbetween the plasma meniscus (i.e., beam emission surface) and the beam extraction grid is important. This study conducts a novel investigation into the dependence of the effective distance <i>d</i>_effon the amount of surface H^-production <i>S</i>_H-. For this purpose, a 3D PIC (three dimensional Particle-in-Cell) simulation is conducted to obtain a model geometry of the extraction region for a H^-ion source with <i>S</i>_H-as a parameter. Based on results, <i>d</i>_effsignificantly depends on <i>S</i>_H-and the H^--electron density ratio (α = <i>n</i>_H-/<i>n_e</i>) in front of the extraction aperture for the same plasma density; as <i>S</i>_H-increases, <i>d</i>_effdecreases. The results suggest that <i>S</i>_H-is critical for controlling <i>d</i>_effand the resultant beam optics extracted from the negative ion source.</p>

  • Access to Document (DOI)
  • CiNii Research

• Analysis of plasma meniscus in a hydrogen electronegative plasma

  Miyamoto K., Hayashi K., Hoshino K., Hatayama A.

  Plasma Sources Science and Technology （Plasma Sources Science and Technology)  31 （ 10 ）  2022.09

  Research paper (scientific journal), Joint Work, Accepted,  ISSN  09630252

  　View Summary

  The emitting surface of an ion beam (plasma meniscus) in the vicinity of the extraction aperture is theoretically investigated. In the present study, the electrons, H+ ions and volume produced H− ions are contained in the electronegative plasma. By solving the one-dimensional Poisson equation, an analytical formula is obtained from the balance between the current reaching a wall and the space charge limited current of negatively charged particles. The analytical formula indicates that the distance, d eff, between the plasma meniscus and the extraction grid includes the ratio of masses of the negative ions and electrons, which is different from that for a plasma containing electrons and single positive ions, and depends on the ratio of the negative ion density to the electron density, α. With increase in the value of α, the distance d eff becomes shorter, and thus the penetration of the electric field for negative ion extraction into the source plasma becomes smaller. This tendency is confirmed by using a three-dimensional particle-in-cell simulation from the results of the contour map of the electrostatic potential near the plasma grid and the location of the plasma meniscus. The reasons why the distance d eff becomes shorter with increase in the value of α are considered to be the larger space charge effect of the negative ions compared with that of the electrons and the decrease in the plasma potential.

  • Access to Document (DOI)

• Plasma physics and control studies planned in JT-60SA for ITER and DEMO operations and risk mitigation

  Yoshida M., Giruzzi G., Aiba N., Artaud J.F., Ayllon-Guerola J., Balbinot L., Beeke O., Belonohy E., Bettini P., Bin W., Bierwage A., Bolzonella T., Bonotto M., Boulbe C., Buermans J., Chernyshova M., Coda S., Coelho R., Davis S., Day C., De Tommasi G., Dibon M., Ejiri A., Falchetto G., Fassina A., Faugeras B., Figini L., Fukumoto M., Futatani S., Galazka K., Garcia J., Garcia-Muñoz M., Garzotti L., Giacomelli L., Giudicotti L., Hall S., Hayashi N., Hoa C., Honda M., Hoshino K., Iafrati M., Iantchenko A., Ide S., Iio S., Imazawa R., Inoue S., Isayama A., Joffrin E., Kamiya K., Ko Y., Kobayashi M., Kobayashi T., Kocsis G., Kovacsik A., Kurki-Suonio T., Lacroix B., Lang P., Lauber P., Louzguiti A., De La Luna E., Marchiori G., Mattei M., Matsuyama A., Mazzi S., Mele A., Michel F., Miyata Y., Morales J., Moreau P., Moro A., Nakano T., Nakata M., Narita E., Neu R., Nicollet S., Nocente M., Nowak S., Orsitto F.P., Ostuni V., Ohtani Y., Oyama N., Pasqualotto R., Pégourié B., Perelli E., Pigatto L., Piccinni C., Pironti A., Platania P., Ploeckl B., Ricci D., Roussel P., Rubino G., Sano R., Särkimäki K., Shinohara K., Soare S., Sozzi C., Sumida S., Suzuki T., Suzuki Y.

  Plasma Physics and Controlled Fusion （Plasma Physics and Controlled Fusion)  64 （ 5 ）  2022.05

  Research paper (scientific journal), Joint Work, Accepted,  ISSN  07413335

  　View Summary

  A large superconducting machine, JT-60SA has been constructed to provide major contributions to the ITER program and DEMO design. For the success of the ITER project and fusion reactor, understanding and development of plasma controllability in ITER and DEMO relevant higher beta regimes are essential. JT-60SA has focused the program on the plasma controllability for scenario development and risk mitigation in ITER as well as on investigating DEMO relevant regimes. This paper summarizes the high research priorities and strategy for the JT-60SA project. Recent works on simulation studies to prepare the plasma physics and control experiments are presented, such as plasma breakdown and equilibrium controls, hybrid and steady-state scenario development, and risk mitigation techniques. Contributions of JT-60SA to ITER and DEMO have been clarified through those studies.

  • Access to Document (DOI)

• Development and Application of SONIC Divertor Simulation Code to Power Exhaust Design of Japanese DEMO Divertor

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

  Processes （Processes)  10 （ 5 ） 872 2022.04

  Research paper (scientific journal), Joint Work, Accepted

  　View Summary

  An integrated divertor simulation code, SONIC, An integrated divertor simulation code, SONIC, has been developed in order to predict a self-consistent transport solution of the plasma, neutral and impurities in the scrape-off layer (SOL) and divertor. SONIC code has contributed to determining the divertor design and power handling scenarios for the Japanese (JA) fusion demonstration (DEMO) reactor. Radiative cooling scenario of Ar impurity seeding and the divertor performance have been demonstrated to evaluate the power exhaust scenarios with . The simulation identified the decay length of the total parallel heat flux profile as being broader than the electron one, because of the ion convective transport from the outer divertor to the upstream SOL, produced by the plasma flow reversal. The flow reversal also reduced the impurity retention in the outer divertor, which may produce the partial detachment. Divertor operation margin of key power exhaust parameters to satisfy the peak was determined in the low of under severe conditions such as reducing radiation loss fraction, i.e., and diffusion coefficients and . The divertor geometry and reference parameters rad) were consistent with the low operation of the JA DEMO concepts. For either severe assumption of or and to their half values, higher operation was required. In addition, recent investigations of physics models (temperature-gradient force on impurity, photon transport, neutral-neutral collision) under the DEMO relevant SOL and divertor condition are presented.

  • Access to Document (DOI)

• Study of negative ion beam emittance characteristic using 3D PIC-MCC simulation

  Miyamoto K., Nagaoka K., Hatayama A., Hoshino K., Nakano H., Shibata T., Tsumori K.

  Journal of Physics: Conference Series （Journal of Physics: Conference Series)  2244 （ 1 ）  2022.04

  Research paper (international conference proceedings), Joint Work, Accepted,  ISSN  17426588

  　View Summary

  It is reported from the measurement of a negative ion beamlet emittance that the characteristic three-Gaussian components are observed in the emittance diagram. The negative ion trajectories are calculated using 3D PIC-MCC simulation in order to clarify the origin of this complicated phase space structure and underlying physical mechanism. The characteristic three-Gaussian components can be reproduced in the emittance diagram from the simulation result. It is verified that the Gaussian components are caused by the negative ions extracted from the different plasma meniscus region, that is, the central region or the region near the edges of the meniscus.

  • Access to Document (DOI)

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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 】

• 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

• 小特集 核融合プラズマおよびダイバータにおけるタングステン研究の進展と課題： 4. タングステン不純物輸送モデリングの進展と課題

  星野一生

  プラズマ・核融合学会誌 87 ( 09 ) 600 - 606 2011.09

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

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Presentations 【 Display / hide 】

Presentations 【 Display / hide 】

• ダイバータプラズマにおける大角度散乱による粒子輸送 磁力線ピッチ角と中性粒子流速の影響

  梅崎大介、松浦秀明、星野一生

  第39回プラズマ・核融合学会年会, 

  2022.11

  , 

  Poster presentation

• 原型炉プラズマ対向壁の燃料インベントリー評価とヘリウム照射効果

  大宅諒、星野一生、朝倉伸幸、坂本宜照、大野哲靖、花田和明

  第39回プラズマ・核融合学会年会, 

  2022.11

  , 

  Oral presentation (general)

• トロイダルリップル及びRMPコイルパリティ差異に着目したJT-60SA周辺プラズマ輸送シミュレーション

  榎本昇悟、田中宏彦、河村学思、松永剛、鈴木康浩、小林政弘、星野一生、梶田信、大野哲靖

  第39回プラズマ・核融合学会年会, 

  2022.11

  , 

  Poster presentation

• PICシミュレーションによる非接触ダイバータプラズマ解析

  星野一生、櫻井陽都、吉田旬汰

  第39回プラズマ・核融合学会年会, 

  2022.11

  , 

  Poster presentation

• RF負イオン源におけるプラズマメニスカス形状の数値解析

  林克哉 、星野一生、宮本賢治、畑山明聖、J. Lettry

  第39回プラズマ・核融合学会年会, 

  2022.11

  , 

  Poster presentation

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

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

• 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。

• Kinetic Modeling of Fusion Edge Plasma and Dynamic Characteristics of Detachemnt Plasmas

  2015.04

  -

  2018.03

  Keio University, Hatayama Akiyoshi, Sawada Keiji, Tsumori Katuyoshi, Kojima Atsushi, Murakami Izumi, Nakamura Hiroaki, Nakashima Yousuke, Lettry Jacques, Grant-in-Aid for Scientific Research (B), Research grant, Coinvestigator(s)

  　View Summary

  The final goal of this study is to develop a new kinetic simulation tool of plasmas, neutrals, and impurities in fusion edge plasmas. Taking into account the non-equilibrium and non-steady characteristics of electron energy distribution function (EEDF), we have done a dynamic simulation of the ELM (Edge Localized Mode). The effect of the ELM on the plasma detachment has been studied. Especially. the effects of the ELM on the MAR (Molecular Activated Recombination) has been analyzed. The results show that the vibrational excited molecules, which play a key for MAR, are effectively produced during the ELM heat pulse. Due to this enhancement, MAR rate is possibly enhanced after the ELM pulse. In addition, a new kinetic impurity transport model has been successfully developed. The model includes neo-classical transport effects of impurities, which becomes important under the steep density/temperature gradient in the core pedestal region before and after the ELM pulse.

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Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• SCIENCE OF ATOMIC ENERGY

  2022

• PRESENTATION TECHNIQUE

  2022

• PLASMA PHYSICS

  2022

• PLASMA PHYSICS

  2022

• INDEPENDENT STUDY ON FUNDAMENTAL SCIENCE AND TECHNOLOGY

  2022

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Memberships in Academic Societies 【 Display / hide 】

Memberships in Academic Societies 【 Display / hide 】

• 日本シミュレーション学会, 

  2022.07

  -

  Present

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

  2001.08

  -

  Present

Committee Experiences 【 Display / hide 】

Committee Experiences 【 Display / hide 】

• 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