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Journal Articles

Analysis of feedback control of magnetic islands via rotational field based on Rutherford model

Uenaga, Issei; Furukawa, Masaru*

Physics of Plasmas, 27(9), p.092501_1 - 092501_11, 2020/09

Times Cited Count：0 Percentile：0.00(Physics, Fluids & Plasmas)

This work uses the Rutherford model for a cylindrical plasma to study the dynamics of magnetic islands under external magnetic perturbations, including both applied rotational magnetic fields and static error magnetic fields. The results show that, in an unstable tearing situation, magnetic islands are completely suppressed by modulating the frequency of the externally applied rotational magnetic field to maintain the phase of the combined external magnetic field to be opposite (or nearly opposite) that of the magnetic islands. The frequency is modulated by using a proportional controller in the simulation, where the frequency of the rotational field is determined by using the island rotation frequency "measured" in the simulation.

Journal Articles

Study of particle behavior for steady-state operation in JT-60U

Kubo, Hirotaka; JT-60 Team

Plasma Science and Technology, 8(1), p.50 - 54, 2006/01

https://doi.org/10.1088/1009-0630/8/1/12

Times Cited Count：2 Percentile：6.80(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Probe measurements; Fundamentals to advanced applications

Amemiya, Hiroshi*; Wada, Motoi*; Toyoda, Hirotaka*; Nakamura, Keiji*; Ando, Akira*; Uehara, Kazuya; Oyama, Koichiro*; Sakai, Osamu*; Tachibana, Kunihide*

Purazuma, Kaku Yugo Gakkai-Shi, 81(7), p.482 - 525, 2005/07

http://ci.nii.ac.jp/naid/110006281949

This article is asked to write by the Japan Society of Plasma Science and Nuclear Fusion Research. The probe diagnostics in fusion plasma is explaind for many readers of the Journal of Plasma and Fusion Research, who have much concerned on various aspects.In section one, the method to estimate the electron temperature and the density as well as the electron energy distribution function with the single probe is given. In section two, the method to estimate the ion temperature and the flow velocity with the double probe is given. The practical measurements are explained introducing the data obtained at JFT-2, JFT-2a and JFT-2M in JAERI tokamak.

Journal Articles

Advances in plasma and fusion simulation and prospects for the future; From a viewpoint of magnetically confined fusion

Kishimoto, Yasuaki

Purazuma, Kaku Yugo Gakkai-Shi, 80(5), p.390 - 395, 2004/05

https://doi.org/10.1585/jspf.80.390

High performance magnetically confined plasma is realized by having structures in plasmas, where different elementary processes with different time and spatial scales are deeply contributing with each other. A research based on large scale simulation is then essential to understand such hierarchical complex plasmas. We discuss the underlying physical process of the structural plasma and present a prospect for future numerical simulations covering a wide dynamical range.

Journal Articles

Recent progress of SOL and divertor plasma studies in Tokamaks

Asakura, Nobuyuki

Purazuma, Kaku Yugo Gakkai-Shi, 80(3), p.190 - 200, 2004/03

https://doi.org/10.1585/jspf.80.190

Understanding of the divertor and Scrape-off Layer (SOL) plasmas has been progressed during improvements of the compact- and closed-geometry tokamak divertors. Developments of new diagnostics viewing the SOL and upstream of the divertor target (with the finest spatial and/or time resolutions) have contributed to understand the physics mechanisms under large variations of the plasma along and perpendicular to the field lines. Four topics: (i) heat and particle transports upstream of the divertor plate, (ii) burst transport of heat and particles towards the divertor, (iii) SOL plasma flow, and (iv) plasma diffusion in SOL, were reviewed.

Journal Articles

Prospect for "multiple-hierarchical complex plasma" where turbulent and laminar flow fluctuations are mixed

Kishimoto, Yasuaki; Idomura, Yasuhiro; Li, J.

Purazuma, Kaku Yugo Gakkai-Shi, 79(5), p.478 - 488, 2003/05

https://doi.org/10.1585/jspf.79.478

This is a collection of review article related to the "Multiple Time and Spatial Scale Plasma Simulation" of various fields including fundamental research area of self-organization, magnetic and laser fusion field, space and astrophysics field where a plasma plays an essential roles.

Journal Articles

Two-dimensional particle simulation of the flow control in SOL and divertor plasmas

Takizuka, Tomonori; Hosokawa, Masanari*; Shimizu, Katsuhiro

Journal of Nuclear Materials, 313-316(1-3), p.1331 - 1334, 2003/03

https://doi.org/10.1016/S0022-3115(02)01513-1

Times Cited Count：15 Percentile：68.14(Materials Science, Multidisciplinary)

In course of tokamak fusion research, particle and heat control is one of the most crucial issues. Helium ash exhaust and impurity retention in the divertor region owe to the plasma flow towards divertor plate. The localization of heat load on the plate depends on the flow pattern. Accordingly, particle and heat control can be achieved by the proper control of the flow in SOL and divertor plasmas. In this paper, the flow control is studied with two-dimensional particle simulations by PARASOL (PARticle Advanced simulation for SOL and divertor plasmas) code. Magnetic field configuration with separatrix like a tokamak divertor configuration is given. Hot particle source is put in the core plasma. Recycling cold particle source is located near the divertor plate. Particle source of gas puff in the SOL plasma is given for the flow control. Divertor biasing is available by changing the electrostatic potential on the plates. Effects of gas puff and biasing on the flow are studied. Controllability is evaluated from simulation results.

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