| Career Summary |
1996.3: Graduated, Faculty of Engineering, Kyoto University
2001.3: Doctor of Energy Science from Kyoto University
2001.4-2004.3: Postdoctoral Researcher, Japan Atomic Energy Research Institute
2004.4-2005.3: Postdoctoral Researcher, Japan Society for the Promotion of Science
2005.4-9: Research Associate, The University of Tokyo
2005.10-: Associate Professor, The University of Tokyo
(2006.9-2006.11: Visiting Scientist, Inst. Fusion Studiees, Univ. Texas at Austin)
(2007.4-2009.03: Visiting Associate Professor, Naitonal Instituite for Fusion Science)
(2008.7-2008.8: Visiting Scientist, Inst. Fusion Studiees, Univ. Texas at Austin)
(2010.4-2011.3: Visiting Associate Professor, Graduate School of Energy Science, Kyoto University)
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| Educational Activities |
Graduate school: Introduction to Plasma Science, Plasma Fusion Science, Nonlinear Science, Exercise Class of Fusion Studies
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| Research Activities |
Method for solving boundary layer (singular perturbation) problems in magnetized plasmas (Refs. 1, 2)
Resonant surfaces exist in magnetically confined fusion plasmas, where the wave frequency coincides with the eigenfrequency of the plasma. The magnetic field line has no tension there, and small effects such as electrical resistivity and inertia play a role in the boundary layer around the resonant surface. To solve this kind of "boundary layer (singular perturbation) problem", a method based on asymptotic perturbation has been conventionally used, although it has several difficulties. We have developed a method that can remove these difficulties.
For some details, click here (in Japanese).
Penetration of error fields in tokamak plasmas and shielding by plasma rotation (Ref. 3)
Tokamaks, which are at the frontier of nuclear fusion development, confine plasmas in an axisymmetric torus. However, tokamaks are not exactly axisymmetric in practice. The non-axisymmetric component of a magnetic field can penetrate the plasma and degrade the quality of the confinement. We have clarified the physics of how the plasma rotation can prevent the penetration of the non-axisymmetric magnetic field via numerical simulation.
For some details, click here (in Japanese).
Stability of ballooning modes in torus plasmas with sheared rotation (Refs. 4, 5)
A huge pressure gradient exists in plasma confinement devices because the plasma has high temperature and density in the core region and low temperature and density in the edge region. Waves in the plasma can become unstable due to the energy of the pressure gradient. We have clarified the physical mechanism of how the plasma rotation can suppress these instabilities.
For some details, click here (in Japanese).
Mechanical equilibrium of torus plasma with toroidal rotation and anisotropic pressure
High-temperature plasma is confined in Ring Trap 1 (RT-1) experiments. The plasma is heated using an electron cyclotron wave. Thus, the plasma can have anisotropic pressure. The plasma can also have toroidal rotation. We are studying the characteristics of the mechanical equilibrium of such plasmas.
For some details, click here (in Japanese).
Magneto-rotational instabilities in accretion disks (Ref. 6)
An accretion disk is a celestial disk-shaped gas or plasma object rotating around a massive object such as a black hole. Magneto-rotational instability may account for the accretion rate of the plasma onto the central object. This instability occurs due to coupling between magnetic and velocity fields. We have clarified properties of the instability stemming from the singularity due to the central object.
For some details, click here (in Japanese).
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Literature
1) M. Furukawa and S. Tokuda, Physics of Plasmas 18, 062502 (2011).
2) M. Furukawa, S. Tokuda and L. -J. Zheng, Physics of Plasmas 17, 052502 (2010).
3) M. Furukawa and L. -J. Zheng, Nuclear Fusion 49, 75018 (2009).
4) M. Furukawa and S. Tokuda, Physical Review Letters 94, 175001 (2005).
5) M. Furukawa, Z. Yoshida, and S. Tokuda, Phys. Plasmas 12, 072517 (2005).
6) M. Furukawa, Z. Yoshida, M. Hirota, and V. Krishan", Astrophysical Journal 659, 1496 (2007).
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| Other Activities |
Member of Physical Society of Japan
Member of Japanese Society of Plasma and Fusion Research
Member of The Japan Society for Industrial and Applied Mathematics
International Tokamak Physics Activity (ITPA), MHD Topical Group Member (2009.2-)
Member of Steering Committee, Division 2, Physical Society of Japan (2008.10-2011.9)
Member of Steering Committee, Plasma Science Union (2009.4-)
Member of Special Committee on Theory and Simulation, Cooperative Planning Board
on Core Plasmas, Japan Atomic Energy Agency (2007.8-)
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| Future Plan |
We plan to study the physics and mathematical science of magnetized plasmas such as fusion plasmas on the basis of theory and simulation.
We select research topics according to our motivation of contributing to the development of electric power generation by nuclear fusion. However, we do not simply contribute to fusion development. We focus on the generality of the problem and study the problem from the view-point of physics and mathematical science. From this standpoint, we not only solve the specific problem, but also solve problems that have the same physics and/or mathematical structures. Therefore, we expect to significantly contribute to many research areas other than fusion development.
Recently, we have been studying "boundary layer (singular perturbation) problems" in fusion plasmas. Pioneers established a method for solving the boundary-layer problem via asymptotic perturbation soon after they started fusion research. However, the method fails in some important situations from the beginning. Moreover, even if it is applicable in principle, the method requires challenging numerical computation in reality. We have developed a new method for solving this boundary-layer problem. Our method does not suffer from the difficulties of the traditional method. We will clarify the relationship between our method and the traditional one mathematically. We will also apply our method to realistic situations, that contributes to the fusion research.
Further, we are fortunate in that we can readily access experimental data generated in the RT-1 device and so on. We are also motivated by these experiments. We will continue to study interesting phenomena observed in these experiments from the view point of physics and mathematical science.
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| Messages to Students |
There is a wide range of spatial and temporal scales associated with plasmas. This is also true of human life. Student life is just a few years. The quality of your life as a student will depend on yourself. You are not able do more than your ability allows you to, however, I hope you will enjoy life as a student as much as you possibly can, and make it a priceless experience.
I think the most important thing is to take action. If you join our laboratory, expect to study seriously in order to help develop a new research field.
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