Details of a Researcher - Hoshino, Kazuo

Hoshino, Kazuo

写真a

Affiliation: Faculty of Science and Technology, Department of Applied Physics and Physico-Informatics （Yagami）

Position: Associate Professor

Related Websites

http://www.ppl.appi.keio.ac.jp

External Links

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Career 【 Display / hide 】

2008.04

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2011.03

Japan Atomic Energy Agency, Sector of Fusion Research and Development, Postdoctoral Fellow
2011.04

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2016.03

Japan Atomic Energy Agency, Sector of Fusion Research and Development, Researcher
2016.04

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2016.06

National Institutes for Quantum and Radiological Science and Technology, Fusion Energy Research and Development Directorate, Senior Researcher
2016.07

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2018.03

National Institutes for Quantum and Radiological Science and Technology, Fusion Energy Research and Development Directorate, Principal Researcher
2018.04

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Present

Keio University, Faculty of Science and Technology, Associate Professor

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Academic Background 【 Display / hide 】

1998.04

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2002.03

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

Japan, University, Graduated
2003.04

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2005.03

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

Japan, Graduate School, Completed, Master's course
2005.04

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2008.03

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

Japan, Graduate School, Completed, Doctoral course

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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

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Research Areas 【 Display / hide 】

Plasma science
Nuclear fusion studies

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Research Keywords 【 Display / hide 】

Plasma
Computer Simulation
Fusion
Divertor Plasma
Ion source plasma

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Papers 【 Display / hide 】

Power exhaust concepts and divertor designs for Japanese and European DEMO fusion reactors

Nobuyuki Asakura and Kazuo Hoshino and Satoshi Kakudate and Fabio Subba and Christian Vorpahl and Yuki Homma and Hiroyasu Utoh and Youji Someya and Yoshiteru Sakamoto and Ryoji Hiwatari and Satoshi Suzuki and Jeong-Ha You and Mattia Siccinio and Gianfranco Federici

Nuclear Fusion （{IOP} Publishing) 2021.10

Research paper (scientific journal), Joint Work, Accepted
- Access to Document (DOI)
Simulation studies of divertor detachment and critical power exhaust parameters for Japanese DEMO design

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

Nuclear Materials and Energy （Nuclear Materials and Energy) 26 2021.03

Research paper (scientific journal), Joint Work, Accepted

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© 2020 The Author(s) Handling of a large thermal power exhausted from the confined plasma is one of the most important issues for ITER and DEMO. A conventional divertor, which has the closed geometry similar to that of ITER and longer leg of 1.6 m, was proposed for the Japanese (JA) DEMO reactor (Rp/ap = 8.5/2.42 m). A radiative cooling scenario of Ar impurity seeding and the divertor performance have been demonstrated by SONIC simulation, in order to evaluate the power exhaust in JA-DEMO 2014 (primary design with Psep ~ 283 MW) and JA-DEMO with higher plasma elongation (a revised design with Psep ~ 235 MW). The divertor operation with the peak qtarget ≤ 10 MWm−2 was determined in the low nesep of 2–3 × 1019 m−3 under the severe conditions of reducing radiation loss fraction, i.e. f*raddiv = (Pradsol + Praddiv)/Psep, and diffusion coefficients (χ and D). The divertor geometry and reference key parameters (f*raddiv ~ 0.8, χ = 1 m2/s and D = 0.3 m2/s) were so far consistent with the power exhaust concepts in the nesep range, and the revised JA-DEMO design has advantages of wider nesep range and enough margin for the divertor operation. For either severe assumption of f*raddiv ~ 0.7 or χ and D to the half value, higher nesep operation was required for the primary design in order to control the peak qtarget ≤ 10 MWm−2, i.e. the operation window was reduced. Applying the two severe assumptions, the divertor operation was difficult in the low nesep range for the both designs.
- Access to Document (DOI)
Study of numerical error of a Eulerian-Lagrangian scheme in the presence of particle source

Ryoko Tatsumi and Kazuo Hoshino and Akiyoshi Hatayama

Computer Physics Communications （Elsevier {BV}) 264 107960 2021.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 00104655

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Eulerian–Lagrangian (EL–LG) scheme is a numerical scheme that tracks pseudo particles in Eulerian cells. It is widely used in the computational fluid dynamics, however, numerical errors associated with a particle source term has not yet been investigated much. Hence this study focuses on numerical errors of EL–LG caused by particle sources. The purposes are: (i) to clarify causes and situations that bring larger numerical errors by source terms and (ii) to suggest an idea to reduce them. For those purposes, we focus on the particle continuity equation and carry out systematic analysis of the numerical error by setting the following three simple cases: Case (A) No source, Case (B) Constant source, and Case (C) source with arbitrary spatial profile. For each case, we have obtained a theoretical expression of the numerical error. It has been clarified that the errors become relatively large when (i) the spatial profile of the particle source has a large gradient and (ii) the source is localized in the region with high flow-velocity. These were caused by the treatment of the particle source: If pseudo particles due to the source are added in a simple way at the start or the end of the time step, this can lead to larger numerical errors. To reduce those errors, a time-averaging scheme has been suggested. Although the analyzed cases are simple, the results obtained in this study would give important knowledge and insight into numerical errors associated with particle sources in EL–LG schemes.
- Access to Document (DOI)
Numerical Simulation Study of the Magnetic Flux Tube Expansion on the Divertor Plasma Parameters by the LINDA Code

ISLAM Md. Shahinul, NAKASHIMA Yousuke, ISHIGURO Seiji, HOSHINO Kazuo, HATAYAMA Akiyoshi, HASEGAWA Hiroki, SAKAMOTO Mizuki

Plasma and Fusion Research （一般社団法人プラズマ・核融合学会) 16 （ 0 ） 2403049 - 2403049 2021

Research paper (scientific journal), Joint Work, Accepted

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In this research, we investigate the effect of magnetic flux tube expansion on the divertor plasma parameters by using the fluid code "LINDA". A comparison between the cylindrical flux tube (without the magnetic flux expansion) and the expansion magnetic flux tube has been undertaken. The aim of the study is to understand the impact of magnetic field expansion on the divertor physics by using the LINDA fluid code. The plasma density (ni) is decreased and parallel velocity is increased (ui||) toward the target plate with the expansion of magnetic field lines near the target plate. The heat and particle fluxes are reduced significantly on the target plate in the case of the expansion mesh configuration. For the case of cylindrical mesh, advection becomes stronger with the decreasing distance from the target plate. In the case of expansion mesh, diffusion is stronger with the decreasing distance from the target plate. These outcomes clearly indicate the effect of the magnetic field structure on the divertor plasma parameters.
- Access to Document (DOI)
Detached helium plasma simulation by a one-dimensional fluid code with detailed collisional-radiative model

Tanaka H., Saeki I., Ohno N., Kajita S., Ido T., Natsume H., Hatayama A., Hoshino K., Sawada K., Goto M.

Physics of Plasmas （Physics of Plasmas) 27 （ 10 ） 102505 2020.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 1070664X

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© 2020 Author(s). To increase the accuracy of a particle, momentum, and energy source terms in the detached helium plasma simulation, rate coefficients with the collisional-radiative model were introduced into the fluid code LINear Divertor Analysis (LINDA). Obtained effective rate coefficients and related source terms were compared with those from the conventional empirical databases. It is shown that a high-density condition in future fusion devices causes larger deviation between the effective and the empirical source terms. One-dimensional detached plasma simulation indicated that the peak amplitude of the plasma density during the rollover is sensitive to the source term difference related to the recombination. This study additionally revealed that the heating effect in the three-body recombination process strongly affects the detached plasma formation and downstream plasma parameters.
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Papers, etc., Registered in KOARA 【 Display / hide 】

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

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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

Introduction and explanation (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

Introduction and explanation (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

Introduction and explanation (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

Introduction and explanation (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

Introduction and explanation (scientific journal), Single Work

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Presentations 【 Display / hide 】

Effect of negative ion sheath on beam extraction in negative hydrogen ion sources

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

International Conference on Ion Sources, 2021.09, Oral Presentation(general)
Investigation of neutral-neutral collision model in the DEMO level divertor by SONIC simulation

K. Hoshino, S. Tokunaga, S. Yamoto, Y. Homma, N. Asakura

The 18th International Workshop on Plasma Edge Theory in Fusion Devices, 2021.09, Poster (general)
Improvement of Neutral Transport Model in SONIC toward DEMO

M. Nakano, S. Yamoto, Y. Homma, N. Asakura

The 18th International Workshop on Plasma Edge Theory in Fusion Devices, 2021.09, Poster (general)
Detached helium plasma simulation with collisional-radiative model

H. Tanaka, I. Saeki, N. Ohno, S. Kajita, T. Ido, H. Natsume, A. Hatayama, K. Hoshino, K. Sawada, M. Goto

The 40th JSST Annual International Conference on Simulation Technology, 2021.09, Oral Presentation(general)
Plasma Exhaust and Divertor Designs in Japan and Europe Broader Approach, DEMO Design Activity

N. Asakura, K. Hoshino, Y. Homma, C. Vorpahl, F. Subba, H. Utoh, Y. Someya, S. Kakudate S. Suzuki, Y. Sakamoto, R. Hiwatari, M. Siccinio, G. Federici, J.-H. You

28th IAEA Fusion Energy Conference (online) , 2021.05, Poster (general)

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

消えるプラズマの時空間構造を支配する物理・化学機構の解明と制御

2020.04

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2024.03

Nagoya University, 大野哲靖, 梶田信, 澤田圭司, 荒巻光利, 星野一生, 田中宏彦, Grant-in-Aid for Scientific Research (A), Research grant, Co-investigator

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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

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2022.03

Naruto University of Education, 宮本賢治, 畑山明聖, 星野一生, Grant-in-Aid for Scientific Research (C), Co-investigator

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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

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2022.03

Keio University, 星野一生, 林伸彦, Grant-in-Aid for Scientific Research (C), No Setting, Principal Investigator

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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

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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, Co-investigator

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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.
Study of the Detached Divertor Plasma under Huge Heat Flux Condition

2015.04

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2018.03

Japan Atomic Energy Agency, Kazuo Hoshino, Grant-in-Aid for Young Scientists (B), Research grant, Principal Investigator

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Control of the detached divertor plasma and the resultant reduction of the divertor heat load are one of the most critical issues on the fusion DEMO design study. In this study, understanding of the detached divertor plasma has progressed by analysis of the experimental data and development of the divertor simulation code has progressed. Control of the detached divertor plasma and reduction of the divertor heat load by using impurity seeding has been also investigated.