Grant-in-Aid for Specialli Promoted Research 2017 - 2022

Plasma Turbulence Observation System (PLATOS) for puzzling out the principles of structural formation and functional expression in turbulent plasmas
- PLATO project -

Research Institute for Applied Mechanics, Kyushu University

Purpose and Background of the Research

Plasma is ubiquitous, as it is said that visible matters of 99% in the universe are in plasma state. It is turbulence that determines the structure and dynamics of plasma. Particularly, the turbulence has been extensively studied in the research of magnetically confined plasmas aiming at nuclear fusion, since it is a key to determine the plasma properties. Thanks to these efforts, a new paradigm has been proposed recently, that is, the couplings between disparate scale fluctuations and structure produces a global scale correlation to determine plasma properties. The purpose of the project is, being based on the paradigm, to clarify the structural formation and function expression of turbulent plasmas.

Research Methods

In the project, a never-existing device, named Plasma Turbulence Observatory (PLATO), is constructed to focus on the physics of turbulent plasmas and its understanding experimentally. The device is the first device to measure the entire cross-sections of turbulent plasma with a spatial resolution of microscale of Lamor radius. The device makes it possible to investigate the reality of cross-scale couplings and turbulence localization, and finally to explore the principles of structural formation and function expression.


The plasma turbulence tomography, using plasma emissions, is the major diagnostic method that has shown the ability of turbulence measurement in a prototype installed on a linear cylindrical device in the previous project on grant-in-aid for scientific research.

Plasma emission and a fluctuation power spectrum obtained with the prototype of plasma tomography on a linear device.

Moreover, in addition to the tomography, PLATO uses heavy ion beam probes (HIBP) and microwaves diagnostics with superior abilities in local and fine measurements. The HIBP ability of simultaneous detection of density, electric field, and magnetic field, is utilized, and turbulence studies are performed in the synthetic manner of these diagnostics.

Expected Research Achievements and Scientific Significance

Torus is a natural shape for magnetic field, and the studies of plasma in such magnetic field structure are important for understanding phenomena in nature and the universe, for example, solar tachocline, transport around accretion disk of a backhole, and so on. Moreover, it is a common subject for physics, chemistry, social science, etc., how fluctuations should govern the structural formation and function expression in a non-equilibrium system. Finally, the project, pursuing the law of panta rhei, complementarily to research of elementary particles, has significance for physics of non-equilibrium that provides natural recognition and future technologies.