KOTARO YAMASAKI

Last Updated :2024/10/02

Affiliations, Positions
Graduate School of Advanced Science and Engineering, Associate Professor
Self-introduction
Plasma diagnostics; Langmuir probe, tomography, Thomson scattering measurement

Basic Information

Major Professional Backgrounds

  • 2020/12/01, Hiroshima University, Graduate School of Advanced Science and Engineering, Assistant Professor
  • 2016/04, 2020/11, Kyushu University, Research Institute for Applied Mechanics, Research Fellow

Educational Backgrounds

  • The University of Tokyo, Graduate School for Engineering, Department of Electrical Engineering and Information Systems, 2013/04, 2016/03
  • The University of Tokyo, Graduate School for Frontier Sciences, Department of Advanced Energy, 2011/04, 2013/03
  • Kyoto University, Faculty of Engineering, 2007/04, 2011/03

Academic Degrees

  • The University of Tokyo

Educational Activity

  • [Bachelor Degree Program] School of Engineering : Cluster 1(Mechanical Systems, Transportation, Material and Energy) : Program of Energy Transform Engineering
  • [Master's Program] Graduate School of Advanced Science and Engineering : Division of Advanced Science and Engineering : Mechanical Engineering Program
  • [Doctoral Program] Graduate School of Advanced Science and Engineering : Division of Advanced Science and Engineering : Mechanical Engineering Program

Research Fields

  • Engineering;Integrated engineering;Nuclear fusion studies

Research Keywords

  • plasma diagnostics
  • plasma
  • spherical tokamak
  • tokamak
  • magnetic reconnection
  • turbulence
  • tomography
  • nuclear fusion
  • plasma physics

Affiliated Academic Societies

  • The Iron and Steel Institute of Japan
  • The Laser Society of Japan
  • the Physical Society of Japan
  • The Japan Society of Plasma Science and Nuclear Fusion Research
  • THE PHYSICAL SOCIETY OF JAPAN
  • The Japan Society of Plasma Science and Nuclear Fusion Research

Educational Activity

Course in Charge

  1. 2024, Liberal Arts Education Program1, 4Term, Introduction to Mechanical Engineering
  2. 2024, Liberal Arts Education Program1, 4Term, General Mechanics II
  3. 2024, Undergraduate Education, 3Term, Practice of Mechanics
  4. 2024, Undergraduate Education, 2Term, Plasma Engineering
  5. 2024, Undergraduate Education, Year, Graduation Thesis
  6. 2024, Graduate Education (Master's Program) , 1Term, Special Exercises on Mechanical Engineering A
  7. 2024, Graduate Education (Master's Program) , 2Term, Special Exercises on Mechanical Engineering A
  8. 2024, Graduate Education (Master's Program) , 3Term, Special Exercises on Mechanical Engineering B
  9. 2024, Graduate Education (Master's Program) , 4Term, Special Exercises on Mechanical Engineering B
  10. 2024, Graduate Education (Master's Program) , Academic Year, Special Study on Mechanical Engineering
  11. 2024, Graduate Education (Master's Program) , 4Term, Advanced Plasma Engineering
  12. 2024, Graduate Education (Doctoral Program) , Academic Year, Special Study on Mechanical Engineering

Research Activities

Academic Papers

  1. Identification of nonlinear effects of background asymmetry on solitary oscillations in a cylindrical plasma, Scientific Reports, 14, 12175, 20240528
  2. Velocity Field Estimation using Tomography in a Cylindrical Plasma, Plasma and Fusion Research, 19, 1201005-1201005, 20240126
  3. Development of the Thomson scattering measurement system for cascade arc device with indirectly heated hollow cathode, Journal of Instrumentation, 18, C11007, 20231101
  4. Development of the Thomson scattering measurement system for cascade arc device with indirectly heated hollow cathode, Journal of Instrumentation, 2023
  5. Rotational movement analysis based on Fourier-rectangular function transform for cylindrical plasma, Journal of Applied Physics, 134, 113302, 20230919
  6. Development of a large-bore plasma window with an indirectly heated hollow cathode, Journal of Applied Physics, 134(9), 093302, 20230907
  7. Water-window x-ray emission from laser-produced Au plasma under optimal target thickness and focus conditions, Physical Review E, 107(6), 065211, 20230628
  8. Generation of stationary high-density cascade arc plasma and application to plasma windows, JAPANESE JOURNAL OF APPLIED PHYSICS, 62(SL), 20230901
  9. Generation of stationary high-density cascade arc plasma and application to plasma windows, Japanese Journal of Applied Physics, 62(SL), SL1009-SL1009, 20230608
  10. A Proposal to Evaluate Electron Temperature and Electron Density Fluctuations Using Dual Wavelength Emission Intensity Tomography in a Linear Plasma, Journal of the Physical Society of Japan, 92(3), 20230227
  11. Enhancement of Gain Coefficient of Li-Like Ion 3d-4f Soft X-ray Laser Oscillation by a Single Resonator, 10(4), 128-128, 20221101
  12. Generation of Highly Charged Au Ion in Laser-Produced Plasma for Water Window X-ray Radiation Sources, Atoms, 10(4), 150, 20221208
  13. Evaluation of self-absorption effect of He I resonance line by measurement of forbidden emission in helium arc jet plasma, Physics of Plasmas, 29(11), 113505, 20221107
  14. Discharge characteristics of steady-state high-density plasma source based on cascade arc discharge with hollow cathode, Review of Scientific Instruments, 93, 053502, 20220506
  15. Construction of a Magnetic Bottle Electron Spectrometer for Electron Energy Measurement in BISER X-Rays and Xe Interaction, Plasma and Fusion Research, 2406020, 20220408
  16. Dynamic interaction between fluctuations with different origins in a linear magnetized plasma, Physics of Plasmas, 28(11), 112302-112302, 20211109
  17. Bayesian inference of ion velocity distribution function from laser-induced fluorescence spectra, Scientific Reports, 11(20810), 20211021
  18. The first observation of 4D tomography measurement of plasma structures and fluctuations, SCIENTIFIC REPORTS, 11(1), 20210219
  19. Proposal of Analysis Method for Pattern Recognition of Two-Dimensional Structure of Plasma, Plasma and Fusion Research, 16, 1201082, 20210618
  20. Fourier-Rectangular Function Analysis of Spatiotemporal Structure of Bursting Phenomenon in a Cylindrical Plasma, Plasma and Fusion Research, 16, 1201075-1201075, 20210607
  21. Measurements of radial profile of isotope density ratio using bulk charge exchange spectroscopy, Review of Scientific Instruments, 92(6), 063509-063509, 20210601
  22. Conceptual design of heavy ion beam probes on the PLATO tokamak, Review of Scientific Instruments, 92(5), 053553-053553, 20210501
  23. Modal polarization analysis using Fourier-rectangular function transform in a cylindrical plasma, Journal of Applied Physics, 129(9), 093301-093301, 20210307
  24. The first observation of 4D tomography measurement of plasma structures and fluctuations, Scientific Reports, 11(1), 202102
  25. Correlation-estimated conditional average method and its application on solitary oscillation in PANTA, Plasma Physics and Controlled Fusion, 63(3), 032001-032001, 20210122
  26. Comparison between Tomography and Langmuir Probe Data in PANTA, Journal of the Physical Society of Japan, 89(9), 093501-093501, 20200915
  27. Impact of helium neutral gas puff on plasma turbulence in linear magnetized argon plasmas, Physics of Plasmas, 202006
  28. Observation of spatiotemporal structures of temperature fluctuations by using of a statistical phase detection method in a linear magnetized plasma, Plasma Physics and Controlled Fusion, 20200501
  29. Magnetic Field Dependence of Plasma Properties Observed with Tomography in PANTA, Plasma and Fusion Research, 20200414
  30. Tomography system for two-dimensional observation of fluctuation in magnetized plasma, Review of Scientific Instruments, 91(3), 202003
  31. Transition between Isotope-Mixing and Nonmixing States in Hydrogen-Deuterium Mixture Plasmas, Physical Review Letters, 124, 025002, 20200114
  32. Using dynamical mode decomposition to extract the limit cycle dynamics of modulated turbulence in a plasma simulation, Plasma Physics and Controlled Fusion, 61(11), 112001-112001, 20191101
  33. Study of turbulence intermittency in linear magnetized plasma, Plasma Physics and Controlled Fusion, 20191101
  34. Ion temperature measurement by laser‐induced fluorescence spectroscopy in panta, IEEJ Transactions on Electrical and Electronic Engineering, 201910
  35. Fourier-Rectangular Function Analysis for Cylindrical Plasma Images, Journal of Applied Physics, 126, 043304, 201907
  36. The isotope effect on impurities and bulk ion particle transport in the Large Helical Device, Nuclear Fusion, 59(5), 056029, 201904
  37. Observations of radially elongated particle flux induced by streamer in a linear magnetized plasma, Physics of Plasmas, 201904
  38. Combined methods of moment vectors and Stokes parameters to analyze tomographic image of plasma turbulence, Physics of Plasmas, 26, 012305, 201901
  39. Observation of the spatial profile of deuterium/hydrogen ratio using bulk charge exchange emission, Plasma and Fusion Research, 13, 1202103, 201808
  40. Measurement of the Local Current Density Inside a Current Sheet Using a Rogowski Coil Array on UTST Merging Plasmas, PLASMA AND FUSION RESEARCH, 13, 1202093, 201807
  41. Determination of spatiotemporal structure of fluctuations by statistical averaging method, Plasma and Fusion Research, 13, 3401105, 201807
  42. Extraction of nonlinear waveform in turbulent plasma, Physics of Plasmas, 25(6), 062304, 20180601
  43. Three-dimensional structure of the streamer in linear plasmas, Journal of the Physical Society of Japan, 87(3), 034501, 2018
  44. Magnetic island dynamics in magnetic reconnection in UTST experiments, Physics of Plasmas, 25(1), 012126, 20180101
  45. Topological bifurcation of helical flows in magnetized plasmas with density gradient and parallel flow shear, PHYSICS OF PLASMAS, 24(11), 112103, 201711
  46. Fast Algorithm for Tomographic Reconstruction for Plasma Emission, Plasma and Fusion Research, 12, 1201045, 201710
  47. A proposal of Fourier-Bessel expansion with optimized ensembles of bases to analyse two dimensional image, REVIEW OF SCIENTIFIC INSTRUMENTS, 88(9), 093507, 201709
  48. Nonlinear Coupling of Drift Waves and High Frequency Fluctuation on PANTA, Plasma and Fusion Research, 12, 1201034, 201707
  49. Generation of Energetic Electrons during Spherical Tokamak Merging in UTST, PLASMA AND FUSION RESEARCH, 11, 2402100, 2016
  50. Laboratory study of diffusion region with electron energization during high guide field reconnection, PHYSICS OF PLASMAS, 22(10), 101202, 201510
  51. Localized electron heating by strong guide-field magnetic reconnection, PHYSICS OF PLASMAS, 22(10), 101201, 201510
  52. Centre-solenoid-free merging start-up of spherical tokamak plasmas in UTST, NUCLEAR FUSION, 55(3), 033013, 201503
  53. Two-Dimensional Electron Temperature and Density Measurement during Strong Guide-Field Reconnection by using Slide-Type Thomson Scattering System, Plasma and Fusion Research, 10, 3402017, 201501
  54. Experimental results of ion heating by magnetic reconnection using external coils, Plasma and Fusion Research, 9(2), 3402038, 2014
  55. Development of a Quasi-steady Equilibrium Field System for Plasma Merging ST Startup Experiments on the UTST Device, Plasma and Fusion Res., 8, 1402139, 201311
  56. Plasmoid-Induced Pull Reconnection Experiments in University of Tokyo Spherical Tokamak, Plasma and Fusion Research, 8, 2401148, 201311
  57. Initiation of Impulsively Fast Magnetic Reconnection Induced by Current Sheet Ejection, Plasma and Fusion Res., 8, 2401112, 201309
  58. Experimental Study of Two-Fluid Effect during Magnetic Reconnection in the UTST Merging Experiment, Plasma and Fusion Research, 8, 2401130, 201309
  59. Electron acceleration by magnetic reconnection during spherical tokamak merging experiment, IEEJ Transactions on Fundamentals and Materials, 133(4), 166-172, 2013
  60. Fourier-Rectangular Function Analysis of Spatiotemporal Structure of Bursting Phenomenon in a Cylindrical Plasma, PLASMA AND FUSION RESEARCH, 16, 20210607
  61. Proposal of Analysis Method for Pattern Recognition of Two-Dimensional Structure of Plasma, PLASMA AND FUSION RESEARCH, 16, 20210618

Invited Lecture, Oral Presentation, Poster Presentation

  1. The radiation trapping effect on the helium line intensity ratio method, K. Yamasaki, R. Hamada, A. Saito, H. Kawazome, T. Nishizawa, J. Kono, Y. Kambara, K. Tomita, Y. Pan, N. Tamura, C. Suzuki, H. Okuno, S. Namba, H. Kawazome, T. Nishizawa, K. Tomita, Y. Pan, N. Tamura, C. Suzuki, H. Okuno, S. Namba, 24th International Stellarator Heliotron Workshop, 2024/09/09, Without Invitation, English, Hiroshima University, International Conference Center Hiroshima, Japan
  2. Two-dimensional turbulence observation using visible light tomography system for fusion plasma study, Kotaro Yamasaki, 8th International Symposium on Fuel and Energy (ISFE2024), 2024/07/01, Without Invitation, English
  3. Impact of the radiative trapping on the helium line intensity ratio method, K. Yamasaki, A. Saito, R. Hamada, H. Kawazome, T. Nishizawa, J. Kono, Y. Kambara, K. Tomita, Y. Pan, N. Tamura, C. Suzuki, H. Okuno, S. Namba, H. Kawazome, T. Nishizawa, J. Kono, Y. Kambara, K. Tomita, Y. Pan, N. Tamura, C. Suzuki, H. Okuno, S. Namba, 26th International Conference on Spectral Line Shapes, 2024/06/06, With Invitation, English, National Institute for Fusion Science, Otsu, Shiga, Japan
  4. Development of large channel diameter plasma window for quantum beam application, K. Yamasaki, K. Okuda, J. Kono, A. Saito, R. Suzuki, Y. Kambara, R. Hamada, Y. Pan, K. Tomita, N. Tamura, C. Suzuki, H. Okuno, S. Namba, Y. Pan, K. Tomita, N. Tamura, C. Suzuki, H. Okuno, 12th Joint Conference on Renewable Energy and Nanotechnology, 2023/12/11, Without Invitation, Japanese, The JCREN Organizing Committee, Thai-Nichi Institute of Technology 1771/1 Pattanakarn Rd., Suanluang, Bangkok 10250, Thailand
  5. Development of a large-bore plasma window with an indirectly heated hollow cathode, K. Yamasaki, K. Okuda, J. Kono, A. Saito, R. Suzuki, R. Hamada, Y. Kambara, Y. Pan, K. Tomita, N. Tamura, C. Suzuki, H. Okuno, S. Namba, 40th annual meeting of plasma and fusion reseach, 2023/11/27, Without Invitation, English
  6. Development of large channel diameter plasma window using indirectly heated hollow cathode, Kotaro Yamasaki, Kosuke Okuda, Jyunya Kono, Ayumu Saito, Daisuke Mori, Yuta Sunada, Oshi Yanagi, Yiming Pan, Kentaro Tomita, Naoki Tamura, Hiroki Okuno, Shinichi Namba, Yiming Pan, Kentaro Tomita, Naoki Tamura, Hiroki Okuno, Shinichi Namba, 7th Asia-Pacific Conference on Plasma Physics, 2023/11/13, With Invitation, English, AAPPS-DPP, Port Messe Nagoya, Japan
  7. Basis function analysis technique for the two-dimensional structure of fluctuation in magnetized plasma, K. Yamasaki, A. Fujisawa, Y. Nagashima, C. Moon, Y. Kawachi, D. Nishimura, T-K. Kobayashi, S. Inagaki, M. Sasaki, Y. Kosuga, T. Yamada, N. Kasuya, A. Fujisawa, Y. Nagashima, C. Moon, Y. Kawachi, D. Nishimura, T-K. Kobayashi, S. Inagaki, M. Sasaki, Y. Kosuga, T. Yamada, N. Kasuya, Global Plasma Forum, 2023/10/18, With Invitation, English, Aomori city, Aomori, Japan
  8. Development of the Thomson scattering measurement system for cascade arc device with indirectly heated hollow cathode, K. Yamasaki, K. Okuda, J. Kono, A. Saito, D. Mori, R. Suzuki, Y. Kambara, R. Hamada, K. Tomita, Y. Pan, N. Tamura, C. Suzuki, H. Okuno, S. Namba, K. Tomita, Y. Pan, N. Tamura, C. Suzuki, H. Okuno, S. Namba, 20th International Symposium on Laser-Aided Plasma Diagnostics (LAPD20), 2023/09/10, Without Invitation, English, Laser-Aided Plasma Diagnostics, Kyoto, Japan, other
  9. Temperature and density measurements of cascade arc discharges with a hollow cathode, Kotaro Yamasaki, Oshi Yanagi, Yuta Sunada, Kosuke Okuda, Daisuke Mori, Jyunya Kono, Ayumu Saito, Md. Anwarul Islam, Naoki Tamura, Hiroki Okuno, Shinichi Namba, the 39th annual meeting of the Japan Society of Plasma Science and Nuclear Fusion Research, 2022/11/22, Without Invitation, Japanese, the Japan Society of Plasma Science and Nuclear Fusion Research, Toyama city, Toyama
  10. Two-dimensional structure of fluctuations and their modal coupling in linear magnetized plasma, K. Yamasaki, A. Fujisawa, Y. Nagashima, C. Moon, S. Inagaki, M. Sasaki, Y. Kosuga, T. Yamada, N. Kasuya, 6th Asia-Pacific Conference on Plasma Physics, 2022/10/13, With Invitation, English, The Association of Asia Pacific Physical Societies Division of Plasma Physics, online
  11. Development of high-density stationary arc plasma source using hollow cathode, K. Yamasaki, O. Yanagi, Y. Sunada, K. Hatta, R. Shigesada, M. Sumino, T. Yamaguchi, Md. Anwarul Islam, T. Endo, N. Tamura, H. Okuno and S. Namba, 2021/11/22, Without Invitation, Japanese
  12. Three-dimensional measurement using tomography systems in a magnetized plasma in linear cylindrical geometry, K. Yamasaki, A. Fujisawa, Y. Nagashima, C. Moon, S. Inagaki, M. Sasaki, Y. Kosuga, T. Yamada, N. Kasuya, 47th EPS Plasma Physics Conference, 2021/06/21, Without Invitation, Japanese, EPS PLASMA 2021, Online
  13. Three-dimensional measurement using tomography systems in a magnetized plasma in linear cylindrical geometry, K. Yamasaki; A. Fujisawa; Y. Nagashima; C. Moon; S. Inagaki; M. Sasaki; Y. Kosuga; T. Yamada; N. Kasuya, 47th EPS Plasma Physics Conference, 2021/06/23
  14. Analysis of the dynamics of nonlinear waves in linear magnetized plasma device PANTA, K. Yamasaki; A. Fujisawa; Y. Nagashima; C. Moon; S. Inagaki; M. Sasaki; Y. Kosuga; T. Yamada; N. Kasuya; T. Ido; T. Akashi; D. Kobayashi; T. Nishimura, The Physical Society of Japan 2020 Autumn Meeting, 2020/09/09
  15. Extraction of the local characteristics of the spatial structure using FRF expansion, 2019/12/01
  16. Analysis of the turbulence tomography imaging data using Fourier Rectangular Function expansion, Kotaro Yamasaki, 2019/09/19
  17. Development of high-resolution tomography system for PLATO, K. Yamasaki; A. Fujisawa; Y. Nagashima; C. Moon; S. Inagaki; M. Sasaki; Y. Kosuga; T. Yamada; N. Kasuya; T. Ido; K. Hasamada; T. Araki; I. Marui; S. Hoshino; T. Akashi; D. Kobayashi; T. Nishimura, The Physical Society of Japan 2019 Autumn Meeting, 2019/09/11
  18. Measuring fluctuation in plasmas using tomography, Kotaro Yamasaki, RIAM forum 2019, 2019/06/06
  19. Extraction of the characteristics of the spatial structure from tomographic reconstruction image, Kotaro Yamasaki, 2019/03/18
  20. Two-dimensional observation of asymmetric structure and solitary wave in linear magnetized plasma, K. Yamasaki; A. Fujisawa; Y. Nagashima; M. Sasaki; S. Inagaki; N. Kasuya; Y; Kosuga; H. Arakawa; T. Yamada; F. Kin; Z. Boyu; K. Hasamada; M. Matsuo; H. Uehara; T. Araki; I. Marui; S. Hoshino, The Physical Society of Japan 2019 Annual (75th) Meeting, 2019/03/17
  21. UTST合体実験における高ガイド磁場リコネクションの浮遊電位計測, 山崎広太郎; 井上静雄; 神尾修治; 渡辺岳典; WANG Anqi; 牛木知彦; 石川裕貴; GUO Xuehan; 中俣浩樹; CHENG C.Z; 井通暁; 小野靖, 核融合エネルギー連合講演会予稿集, 2014
  22. 26pEA-3 Non-steady and Fast Magnetic Reconnection in Laboratory Experiment, Inomoto M; Ono Y; Kamio S; Kuwahata A; Watanabe T. G; Ito T; Kadowaki K; Takemura K; Yamasaki K; Yamada T, Meeting Abstracts of the Physical Society of Japan, 2013, The Physical Society of Japan

Awards

  1. 2023/12/12, The 12th Joint Conference on Renewable Energy and Nanotechnology Best presentation award, Chair of The 12th Joint Conference of Renewable Energy and Nanotechnology (JCREN), Development of large channel diameter plasma window for quantum beam application
  2. 2019/10, JT-60 collaboration research award, National Institutes for Quantum Radiological Science and Technology
  3. 2014/12, Student Presentation Award, A3 Foresight Workshop
  4. 2014/11, Young Researcher's award, The Japan Society of Plasma Science and Nuclear Fusion Research

External Funds

Acceptance Results of Competitive Funds

  1. Research grant, Elucidating the interplay of turbulences in magnetized plasma using 3D wavenumber spectrum, temperature, density and flow observation., 2024/04/01, 2025/03/31
  2. Grants-in-Aid for Scientific Research, 2024/04/01, 2027/03/31
  3. NIFS Collaboration Research Program, 2024/04/01, 2025/03/31
  4. 2023/04/01, 2024/03/31
  5. 2023/06, 2025/05
  6. FY2023 NIFS General Collaboration Project, Observation of the electron current density profile using the triple grating spectrometer, 2023/04, 2024/03
  7. 2022/10, 2023/09
  8. 2022/04, 2023/03
  9. Collaborative Research 2022, 2022/04, 2023/03
  10. 2022/06, 2023/05
  11. 2021/12, 2021/11
  12. Grants-in-Aid for Scientific Research Grant-in-Aid for Early-Career Scientists, 2020/04, 2024/03
  13. 傍熱型ホローカソードを用いたプラズマウインドウの実用化, 2021/07, 2022/06
  14. Investigation on the mechanism of plasma window using Thomson-Rayleigh scattering measurement, 2021/04, 2022/03
  15. Detailed observation of turbulent/nonlinear oscillation in magnetized plasma using local tomography, 2017/04, 2019/03

Social Activities

Organizing Academic Conferences, etc.

  1. ISFE2024, Program committee, 2407/01, 2407/02
  2. ISHW2024
  3. Laser Society of Japan, Local organizer, 2024/03, 2025/03

History as Peer Reviews of Academic Papers

  1. 2024, Fusion Science and Technology, Others, reviewer, 2
  2. 2024, Review of Scientific Instruments, Others, reviewer, 1
  3. 2024, Nuclear Fusion, Others, reviewer, 2
  4. 2023, Fusion Science and Technology, Others, reviewer, 1
  5. 2023, Review of Scientific Instruments, Others, reviewer, 1
  6. 2023, Journal of Instrumentation, Others, Reviewer, 1
  7. 2021, The Japan Institute of Energy, Others, Reviewer, 1
  8. 2023, Plasma and Fusion Research, Others, Reviewer, 1
  9. 2023, Plasma Physics and Controlled Fusion, Others, Reviewer, 1
  10. 2023, Physics of Plasmas, Others, Reviewer, 2
  11. 2019, Plasma and Fusion Research, Others, Reviewer, 1
  12. 2022, Review of Scientific Instruments, Others, Reviewer, 1