Zensho Yoshida / Professor / Division of Transdisciplinary Sciences
Department of Advanced Energy / / Plasma Physics, Nonlinear Science, Fusion Energy

Career Summary
1980: Graduated, Faculty of Engineering, The University of Tokyo
1982-83: Graduate student at Courant Institute of Mathematical Sciences, NYU
1985: Doctor of Engineering from The University of Tokyo
1985: Lecturer, The University of Tokyo
1986: Associate Professor, The University of Tokyo
1999: Professor, The University of Tokyo
Educational Activities
Graduate school: Nonlinear Science, Basic Course on Plasma Physics
Faculty of Engineering: Applied Physics I ~ IV
Research Activities
Diversity of the universe, which has seemed insuperable in previous approaches,
may take on a new character in the context "nonlinear science" and the theory
of gcollective phenomenah -- the paradigm of physics is "plasma".
There are many exciting problems in the scope;
Examples are the catastrophic eruption of plasma (solar flare) at the sun surface,
the corresponding activity of aurora, chaotic (partially periodic and partially random)
emissions from pulsars, and the creation of spectacular spiral patterns in galaxies.
The aim of our study is to explore the diversity of plasma structures in nature.
They will provide us with hints of essential ingredients needed to produce fusion plasmas
(an ultimate energy source) or anti-matter plasmas.
Our recent researches are focused on the interesting structures emerging from "flows" in plasmas.

Figure 1: Theoretical model of Jupiter's magnetosphere. A high energy-density plasma is
confined by the hydrodynamic pressure of high-speed rotation.

Figure 2:  Pure-electron plasma confined by the "magnetosphere" of the Proto-RT device.
By controlling the electric field potential (b), stable confinement has been demonstrated.

1) Z. Yoshida, "Mathematical Physics of Collective Phenomena" (Iwanami, 1995), Monograph in Japanese.
2) Z. Yoshida, "Introduction to Nonlinear Science" (Iwanami, 1998), Monograph in Japanese.
3) Z. Yoshida, "Applied Functional Analysis", new edition, (Saiensu, 2006), Monograph in Japanese.
4) Z. Yoshida, "Nonlinear Science ---The Challenge of Complex Systems" (Springer-Verlag, Berlin-Heidelberg, 2010), Monograph.
5) Z. Yoshida and Y. Giga, Remarks on spectra of operator rot, Math. Z. 204 (1990), 235-245.
6) Z. Yoshida, H. Asakura, H. Kakuno, J. Morikawa, K. Takemura, S. Takizawa, and T. Uchida,
Anomalous resistance Induced by chaos of electron motion, Phys. Rev. Lett. 81 (1998), 245-246.
7) S.M. Mahajan and Z. Yoshida, Double curl Beltrami flow - diamagnetic structures, Phys. Rev. Lett. 81 (1998), 4863-4866.
8) Z. Yoshida and S.M. Mahajan, Variational principles and self-organization in two-fluid plasmas, Phys. Rev. Lett. 88 (2002), 095001.
9) Z. Yoshida, H. Saitoh, J. Morikawa, Y. Yano, S. Watanabe and Y. Ogawa, Magnetospheric vortex formation: self-organized confinement of charged particles, Phys. Rev. Lett. 104 (2010), 235004 1-4.
10) Z. Yoshida and P. J. Morrison, Epi-two-dimensional fluid flow: A new topological paradigm for dimensionality, Phys. Rev. Lett. 119 (2017), 244501 1-5.
Other Activities
Chern Professor, Mathematical Science Reseach Institute (Berkeley, USA)(2018).
Course Director of the College of Plasma Physics, International Center for Theoretical Physics (Trieste, Italy) (1998--).
President, Japanese Society of Plasma and Fusion Research (2017-2019).
Chairman of Division 2 (plasma physics), Japanese Physical Society (2003-2004).
Editor-in-Chief, Journal of Plasma and Fusion Research (2004-2006), Editor, Progress of Theoretiucal and Experimental Physics.
Science Advisor, MEXT, Government of Japan (2004-2010).
Member of Science Council of Japan (2017--).
Future Plan
The RT-1 project is aiming at developing an innovative method of plasma confinement.
The exploration includes many different path-breaking challenges of both
experimental and theoretical physics.
For example, the study of equilibrium and stability of flowing plasma needs
development of new methods of mathematical analysis.
The central theme of recent research is the effect of "flows" in plasmas.
A novel definition of "plasma", which we are proposing,
is a nonlinear coupling of matter and field (the electromagnetic field is
the most important element, but other fields of interactions may also be
included in astronomical or high-energy systems).
A flow, representing a collective motion of matter,
is seemed as a nonlinear field interacting with other fields representing forces.
The coupled dynamics has interesting non-canonical, non-Hermitian, multi-scale properties,
which are underlying a variety of unknown structures and phenomena in the universe.

Figure 3: RT-1 device. A super-conducting magnet is levitated in the vacuum chamber,
producing a dipole magnetic field and creating a magnetospheric plasma configuration
in the laboratory.

Figure 4: Laboratory magnetosphere plasma produced by the RT-1 device.

Messages to Students
Physical and mathematical sciences have developed elegant foundations and sophisticated methodologies,
which are prerequisites for students and young researchers to challenge new problems.
One might feel that the frontier is rather far to reach.
But, nonetheless, there are a plenty of exciting problems
that will need totally innovative ideas of young generation.