22T2
Frontier Physics of Extremely non-Equilibrium Plasmasᴗ㝀ࣈࣚࢫ࣏∸⌦Ꮥࡡ᭩๑⥲Kimitaka Itoh௿⸠පᏏNational Institute for Fusion Science, Toki, 509-5292 JapanItoh Research Center for Plasma Turbulence, Kyushu University, Kasuga, 816-8580, Japanᰶ⼝ྙ⛁Ꮥ◂✪ᡜ㸯509-5292 ᒪ㜟┬ᅰᒪᕰୖ▴⏣322-06
ஐᕗኬᏕ௿⸠ᴗ㝀ࣈࣚࢫ࣏◂✪㏻ᦘࢬࣤࢰ࣭㸯816-8580 ⚗ᒱ┬᫋᪝ᕰ᫋᪝පᅧ6-1
The expanding frontiers of extreme state plasmas are briefly overviewed. One thread of thoughts thatunifies the progresses, which have been achieved in subdivided communities on specific parameters andconfigurations of plasmas, is explained. Synthetic researches on extreme state plasmas far fromequilibrium are introduced, and the research on turbulence, fields and structure formation is illustrated.
The futurology is discussed from this point of view.

1. Problem definition
The empirical knowledge of mankind aboutplasmas has dramatically expanded and now covers
those with extreme parameters, e.g., the*hightemperatureplasmasinmagnetic
confinement devices (several tens of keV),* high density plasmas in laser-produced plasmas(thousand times of solid density),* strong turbulence in basic as well as fusion
plasma experimental devices,* intense charge beam (~108A in 5µ φ),* extremely fine resolution of plasma structure inplasma processing,* approach to precise dynamics in solar plasmas,* emission of photons by plasmas in early universe,* high energy density quark-gluon plasmas,* plasma interacting with genes, cells and organs,etc. (See ref.[1]-[5] for introduction to varieties ofextreme state plasmas.) Efforts to unify
understanding from empirical progresses that havebeen achieved for specific plasmas (e.g., magneticfusion, inertial fusion, plasma processing, spaceastro plasmas, bio plasmas, etc.) have been pursued.
For example, the ‘Research network on nonequilibrium and extreme state plasmas’ project [6]has been launched, in order to accelerate the leadingedge of plasma physics in the arena of modernscience. (It is selected in ‘Japanese Master Plan ofLarge Research Projects’ by Science Council ofJapan [7].) Key physics area of extreme state
plasmas is the deviation from thermal equilibrium,
evolution of turbulence, and dynamical structureformation, which are illuminated here.
2. Physics picture of plasma turbulence
Importance of turbulence in understanding andapplying plasmas has been recognized for morethan five decades of plasma research.
The moststimulating advancements are the change of view
from ‘linear, local and deterministic’ picture to‘nonlinear, nonlocal and probabilistic’ picture.
The nonlinear mechanisms are essential not only inthe suppression processes, but also in thegeneration processes of turbulence.
(E.g.,
subcritical excitation of instabilities and nonlinear
drive of meso and macroscopic fluctuations by
micro turbulence have been understood in detail.)
3. Advanced understanding
The quantitative measurements of nonlinear
processes in plasma turbulence have been realized
and made advancement of scientific knowledge, as
is explained in this talk.
The generation of meso and macroscopic flows
by microscopic turbulence is an essential processthat governs the structure formation in nature.
Turbulences mix inhomogeneous matters, so as to‘homogenize’ the media.
At the same time,
turbulence generates the meso and macroscopic
axial vector fields (such as zonal flow, zonal
magnetic fields, mean electric-field/flow, and meanmagnetic field), which induce the steep spatial
gradient of turbulence fields, thus tends to sharpen
the edge (interface) of inhomogeneous plasmas,
which shows a clear outline of global structure.
The discovery of zonal magnetic fields is the firstexperimental evidence that the micro thermal
convection generates the large-scale magneticstructure, which has long been accepted as ‘dynamo
hypothesis’.
These
twoactions,i.e.,homogenization and sustainment of interface,
govern the generation and decay of ‘structures’ inplasmas. This partly answers the historical enigma
of the law of ‘panta rhei’.
The clarification of origin of anomaloustransport in fusion devices, has also strong impact.

Fig.1: Near future breakthrough and innovations, which are driven by plasma physics [6].

The understanding of H-mode and the experimental
identification of zonal flow have decisive roles in
the future perspective of the burning plasmas in
ITER.
Following illustrative examples are described:* The progress in the statistical theory of plasma
turbulence, in which the important role of‘incoherent’ part by nonlinear interaction has beenhighlighted [8] (the phase space granulation,stochastic forces, and probabilistic transitions etc.);* The first-principle-based experiments, in which
the quantitative verification of theoretical modellinghas been performed.
3. Summary
Researchers on plasmas have realized various
kinds of extreme state plasmas, which will provide
arena for the development of future physics andscience in general. Progresses, which have beenachieved in subdivided communities on specificparameters and configurations of plasmas, can beaccelerated by a unified principle of plasma physics.
As an example, the synthetic research project on
extreme state plasmas far from equilibrium isintroduced, and the research on turbulence, fields
and structure formation is illustrated.
Thefuturology is discussed based on the planning of
this project (See the figure 1).

Acknowledgments
This article is dedicated to the memory of Prof.
Shoich Yoshikawa.
The author acknowledges
collaborations with many colleagues, in particular,Profs. S.-I. Itoh and P. H. Diamond. It is partially
supported by Grant-in-Aid for Scientific Research
JSPS (21224014).
References[1] S.-I. Itoh: J. Plasma Fusion Res. 86 (2010) 334[2] R. Kodama: this conference 23T1; R. Kodama, et al.,Nature 432 (2004) 1005
[3] A. Fujisawa: Nucl. Fusion 49 (2009) 013001[4] R. Hatakeyama and T. Kaneko: Plasma and Fusion
Res.: 6 (2011) 1106011[5] For further reading on extreme state plasmas:
http://ppe.coe.kumamoto-u.ac.jp/ (plasma bioelectrics),
http://plasma.ed.kyushu-u.ac.jp/~plasmanano-pj/(nanoplasma interface),
http://phonon.nifs.ac.jp/ (nonequilibrium rf science),
http://hinode.nao.ac.jp/publ/hsc_paper_main.shtml (solarplasmas),[6] S.-I. Itoh et al.: J. Plasma Fusion Res. 87 (2011) 371[7] Science Council of Japan (2010):
http://www.scj.go.jp/ja/info/kohyo/pdf/kohyo-21-t902.pdf,[8] P. H. Diamond, S.-I. Itoh, K. Itoh: Physical Kinetics
of Turbulent Plasmas (Cambridge University Press,2010)