Organized sessions

Nov. 8th 15:00-18:00(JST)

Structure formation and sustainability

In magnetic confinement plasmas, it is found that the transport process and the stability of the plasmas are related to a given characteristics of the structure of the system such as symmetry. On the other hand, confined plasma is often observed to spontaneously form some characteristic structures and show transitions among them, which drastically change the confinement properties of the plasmas. To realize sustainable fusion reactor, this unit aims at exploring the mechanism between the structure of the system and physics in it and the self-organization and transition processes of the structures in nonequilibrium open system as fusion plasma. This session is organized to introduce the aims of the research activities in this unit as follows. The overall research plan of the unit will be introduced by unit members Dr. Hiroyuki Yamaguchi (NIFS) and Dr. Hiromi Takahashi. Then, review talk on the history and the prospective of the research activities on the relationship between the symmetry of the confinement system and the transport process and stability of magnetic confinement plasma by Prof. Per Helander (Max Planck Institute for Plasma Physics). Next, two invited talks are given from the other natural science field than plasma physics, in order to introduce new perspectives to the research activity in the unit : “Physics of active matter and self-organization phenomena” by Dr. Takuma Sugi (Hiroshima Univ.)  and “Principle of maximum entropy production in phase-transition phenomena” by Dr. Takahiko Ban (Osaka Univ.).

Nov. 8th 15:00-18:00(JST)

Safety science for nuclear fusion

This session is organized by the UNIT group relating to the Safety Science Technologies for Fusion DEMO. We investigate what issues remain for the future social implementation of nuclear fusion power plants, based on fundamental research. For highly safe and beneficial system will be shared as an energy plant that is easy for society to use. It is preferable to use nuclear fusion energy not only as a conventional plant for power generation but also as hybrid energy plants that consider hydrogen production using residual heat for high energy efficiency. The outline of the program is presented by N. Ashikawa (NIFS). An international invited speaker, Prof. Ian Chapman in UKAEA (UK), presents the various research institutes for the next generation nuclear fusion research in UKAEA. As knowledge from outside the fusion technologies, two topics, “Current state of electric power systems in Japan and expectations for fusion energies” by Dr. J. Baba (Univ. of Tokyo) and “Modeling a sense of security, ”Anshin-kan”” by Prof. H. Shoji (Chuo Univ.) are presented. We will lead to solving the issues of nuclear fusion plants through these interesting presentations from a new perspective.

Nov. 9th 9:00-12:00(JST)

Plasma quantum processes

The scope of this organized session is atomic and molecular processes in plasmas, development of plasma spectroscopy, theory, simulation, and modeling with the aid of detailed atomic and molecular processes, and application of atomic and molecular process and database to create interdisciplinary research fields. This organized session aims to present academic plans for our unit, and to discuss prospects of our future. The session consists of three parts. In the first part, our unit theme and academic plans will be presented by Prof. Izumi Murakami (NIFS). Then, a main issue of our research subjects: development of collisional radiative model for non-LTE plasmas and atomic and molecular databases, will be discussed in detail by Dr. Yuri Ralchenko (NIST, USA). In the last part devoted to discussions for prospects of emerging collaborations, three relevant invited talks on highly charged ion physics and spectroscopy by Prof. Nobuyuki Nakamura (ILS/UEC), high-power laser matter interaction by Prof. Yasuhiro Kuramitsu (Osaka Univ), and muon catalyzed fusion by Prof. Yasushi Kino (Tohoku Univ), will be presented.

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Nov. 9th 9:00-12:00(JST)

Advanced superconductivity and cryogenics

Based on NIFS research results on applied superconductivity and cryogenics, this unit conducts academic research to establish attractive, versatile and innovative superconducting magnet technology and highly reliable cryogenic technology. In addition to the long-term goal of realizing nuclear fusion power generation, we aim to realize a carbon-neutral society as a medium- and short-term goal. The superconducting materials studied range from metals to oxides to MgB2. Various cooling methods are also discussed, including liquid hydrogen cooling. This session will introduce the contents of the units in the areas of Cryogenics, Advanced Superconducting Wires, and Superconductors/Coils. In addition, there will be two lectures by overseas researchers and two lectures by domestic researchers.

Nov. 9th 15:00-18:00(JST)

Phase space turbulence

In this unit, motivated by the anomalous transport problem in magnetically confined fusion plasmas, formulation of nonlinear wave-particle interaction in turbulent field is advanced. For the fusion directed goal, existence of phase-space structures is experimentally examined and roles of phase-space turbulence on anomalous transport are investigated. A synergetic approach of cutting-edge diagnostic systems and state-of-the-art kinetic simulations propels understanding of background physics. The session is organized as follows. Overall strategy of the unit activity is presented by Dr. Tatsuya Kobayashi (NIFS). Current status and perspective of diagnostic development for the velocity space measurement using different diagnostic concepts is overviewed by Dr. Tokihiko Tokuzawa (NIFS). In the following session, a basic theoretical background of the phase-space turbulence in fusion plasmas is reviewed by Dr. Maxime Lesur (University of Lorraine). Phase-space structure formation is a general phenomenon in collisionless plasmas, and is known to occur in systems other than magnetically confined fusion plasmas. Nonlinear characteristics vary in different plasma systems, therefore comparing different cases is beneficial for a general understanding of the phase-space structure formation. As a first step, an overview of the nonlinear wave-particle interaction in the laser wake-field plasma acceleration study is given by Dr. Masaki Kando (KPSI, QST).

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Nov. 9th 15:00-18:00(JST)

Meta-hierarchy dynamics

Natural phenomena spanning a wide range of spatio-temporal scales and parameter domains have often been understood by separating and connecting them in various "hierarchies" in reductionistic manners. Fusion sciences explore various multi-scale and multi-physics phenomena spreading over the spatio-temporal scale from the microscopic particle motions to the macroscopic fluid motions. The collective motion exhibits various structures in the plasmas and the materials facing the plasmas. Even though the experimental, theoretical, and numerical studies have made great progresses, a complicated issue has emergerd in the practical facts that some phenomema cannot be simply separated into "hierarchical" structures. i.e., it is not enough to connect reduced elements, but it is required to integrate complex processes of the multi-scale and multi-physics phenomena. The unit pursues “hierarchical” structures and their dynamics in “Turbulence and flows with inherent hierarchies”, “Local and global transport”, “Energy channels of electromagnetic fields and atoms and molecules under anisotropic velocity distribution”, and “Interatictions between the peripheral plasma and the surface of matter”, as well as the physical modeling and universality exploration for multi-scale nature. In the organized session, we discuss the current research trends and new research developments regarding the above unit theme "meta-hierarchy dynamics".

Nov. 10th 9:00-12:00(JST)

S&I: Sensing and intellectulization

In recent years, data science techniques have made great advances. By finding relationships among a large amount of data, we can extract recognizable patterns. We believe that there are two major applications of data science. The first is to advance our understanding of physical phenomena, and the second is to sophisticate the controlling method. Fusion plasma is quite complex and beyond human intuitive understanding. Decomposition of the data into a small number of important elements is the key concept. So-called "sparse modeling" is mainly used to organize the data. To retrieve internal variables from tomography measurements and to extract important parameters essential for the core plasma transport are good examples. The second is to advance engineering control methods. Even if we cannot fully understand the behavior of complex plasmas, if we can predict their behavior, it will be possible to control plasma, which will greatly contribute to the realization of a fusion power plant, where measurable data will be extremely limited. These advanced methods will be further enhanced by advanced diagnostics. These include plasma electron temperature and density measurement with unprecedented spatial and temporal resolution, high-precision fluctuation measurement methods, and infrared image detection. The acquired data will be analyzed using data science, which is complementary to conventional analysis. The maximum amount of useful information will be thereby extracted. Furthermore, complex data are converted into visual, auditory, tactile, and other information to elucidate the structures and correlations hidden within the data interactively.

Nov. 10th 9:00-12:00(JST)

Ultrahigh-flux concerting materials

Materials for fusion and other nuclear reactors, aerospace crafts, chemical plants etc. are used under extreme conditions of localized stress and steep gradient of temperature and composition. In addition, radiation damage is also overlapping under neutron and other irradiation conditions, leading to ultrahigh flux of energy and various particles in materials. Such non-equilibrium conditions induce amorphous and metastable compounds (metastable phase), and self-organization of constituent atoms including crystal lattice defects. Even though formation of the metastable phase and mesoscale patterns has been analyzed and well simulated by experiments and calculations, their physics are still incomplete, novel and very interesting to reveal how the self-organization phase and patterns induce the macroscopic properties. Based on the physics, the non-equilibrium self-organization structure can be correlated with the material properties, and enables us for materials design to accelerate the adaptive structures to the extreme conditions. Our research unit is aiming a paradigm shift from resistant and stable materials to adaptive and metastable materials, leading to creation of novel materials. This research unit investigates structural and functional materials. The materials for investigations consist of metals and ceramics, however their boundary is not necessarily clear. The meta-states, such as ceramic metals and metallic ceramics, are expected to create novel materials. The fabrication for the meta-state materials is generally composed of microstructural control by non-equilibrium hybrid processes. From a viewpoint of condensed matter physics, control of collective atoms dynamics including crystal lattice defects in materials is indivisible and continuum through the engineering stages for the production and use of materials, thus the research unit seeks their comprehensive understanding and systematization.

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Nov. 10th 15:00-18:00(JST)

Transports in plasma multi-phase matter system

Steady-state operation of a fusion reactor requires sophisticated control of energy and particle transport. Energy is converted from thermal to kinetic energies, to light, and to electromagnetic waves, which further interact with matter. Meanwhile, materials circulating in the system undergo phase transitions between plasma, gas, liquid, and solid. The purpose of this unit is to comprehensively understand energy and particle transport across such multiple phase states, including interactions among the phases, and to establish a new picture of fusion reactor systems. In the transport of thermal energy, we focus on the conversion between kinetic energy of charged particles, light and electromagnetic waves via atomic and molecular processes, the role of thermal instability etc. Furthermore, by viewing these physics as the interaction between light and matter, we aim to expand our research into areas, such as the formation of organic molecules in space and plasma biotechnology. For particle circulation, this is taken as "non-equilibrium cross transport". For example, in the case of plasma and neutral particles, the research will be conducted by considering both the control of plasma by neutral particles (micro) and the control of particle circulation by neutral gas (macro), each from a bird's-eye viewpoint. For the solid materials of the device wall of a fusion reactor, we will analyze the mass transfer phenomena between dissimilar materials and the metal to be bonded with atomic-level precision, and elucidate the question "Why is a strong joint with very few voids (high continuity) possible? from a microscopic viewpoint. The results obtained in this research have potential for a wide range of engineering applications, including aerospace and electronics fields.

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Nov. 10th 15:00-18:00(JST)

Plasma Apparatus

TBD

Nov. 11th 9:00-12:00(JST)

Complex global simulation

The purpose of this organized session is to discuss the research plan of the Complex Global Simulation Unit and the cutting-edge research activities included in the scope of the interdisciplinary research of this unit. The Complex Global Simulation Unit aims to develop simulation methods that couple different hierarchies and physical models to realize global simulations that predict and elucidate the behavior of entire physical systems that cannot be handled by simulations based on a single system of fundamental physical equations. In this session, the research plan of the unit will be introduced by unit members Y. Todo (NIFS) and S. Goto (Osaka University), and two invited talks will be given:

  • A. Spitkovsky (Princeton University) "Computational high-energy astrophysics (tentative title)"
  • K. Nakajima (The University of Tokyo) "Integration of 3D simulation of strong earthquake ground motion and real-time data assimilation (tentative title)"

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