Experimental study of nonlinear processes in edge turbulence of toroidal plasmas

JFT-2M Group, CHS Group

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

This paper presents experimental studies of nonlinear processes between meso-scale structures and turbulent fluctuations, by use of bispectral analysis, in the edge region of toroidal plasmas. In ohmically heated plasmas of the JFT-2Mtokamak, the drift wave-zonal flow system is investigated by observation of the potential fluctuations. The total bicoherence is composed of two components, i.e., the peak at the geodesic acoustic mode (GAM) frequency and broadband distribution. The biphase is also obtained, which indicates the phase angle of coherent interaction between GAM oscillations and broadband fluctuations. Bispectral functions (e.g., magnitude and phase) give an order-of-estimate agreement for the drift wave-zonal flow systems. Bicoherence analysis is also applied to the edge plasmas of the high-confinement mode (H-mode) of the Compact Helical System (CHS). In the case of CHS plasmas, nonlinear couplings in a system composed of coherent global magneto-hydrodynamic (MHD) oscillations and broadband fluctuations (up to hundreds kHz range) have been observed. Bispectral analysis enhances our understanding of the self-regulation systems of various toroidal plasmas in which strong turbulence and meso-scale structures coexist.

Original languageEnglish
Article number041
JournalPlasma and Fusion Research
Volume1
DOIs
Publication statusPublished - Jan 1 2006

Fingerprint

toroidal plasmas
turbulence
broadband
oscillations
acoustics
frequency distribution
phase shift
hydrodynamics
estimates
interactions

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Cite this

Experimental study of nonlinear processes in edge turbulence of toroidal plasmas. / JFT-2M Group; CHS Group.

In: Plasma and Fusion Research, Vol. 1, 041, 01.01.2006.

Research output: Contribution to journalArticle

@article{1aa4052f060f44eda7bd26df350501b7,
title = "Experimental study of nonlinear processes in edge turbulence of toroidal plasmas",
abstract = "This paper presents experimental studies of nonlinear processes between meso-scale structures and turbulent fluctuations, by use of bispectral analysis, in the edge region of toroidal plasmas. In ohmically heated plasmas of the JFT-2Mtokamak, the drift wave-zonal flow system is investigated by observation of the potential fluctuations. The total bicoherence is composed of two components, i.e., the peak at the geodesic acoustic mode (GAM) frequency and broadband distribution. The biphase is also obtained, which indicates the phase angle of coherent interaction between GAM oscillations and broadband fluctuations. Bispectral functions (e.g., magnitude and phase) give an order-of-estimate agreement for the drift wave-zonal flow systems. Bicoherence analysis is also applied to the edge plasmas of the high-confinement mode (H-mode) of the Compact Helical System (CHS). In the case of CHS plasmas, nonlinear couplings in a system composed of coherent global magneto-hydrodynamic (MHD) oscillations and broadband fluctuations (up to hundreds kHz range) have been observed. Bispectral analysis enhances our understanding of the self-regulation systems of various toroidal plasmas in which strong turbulence and meso-scale structures coexist.",
author = "{JFT-2M Group} and {CHS Group} and Yoshihiko Nagashima and Katsumichi Hoshino and Kenichi Nagaoka and Kouji Shinohara and Akihide Fujisawa and Kazuya Uehara and Yoshinori Kusama and Katsumi Ida and Yasuo Yoshimura and Shoichi Okamura and Keisuke Matsuoka and Akira Ejiri and Yuichi Takase and Kimitaka Itoh and Masatoshi Yagi and Itoh, {Sanae I.}",
year = "2006",
month = "1",
day = "1",
doi = "10.1585/pfr.1.041",
language = "English",
volume = "1",
journal = "Plasma and Fusion Research",
issn = "1880-6821",
publisher = "The Japan Society of Plasma Science and Nuclear Fusion Research (JSPF)",

}

TY - JOUR

T1 - Experimental study of nonlinear processes in edge turbulence of toroidal plasmas

AU - JFT-2M Group

AU - CHS Group

AU - Nagashima, Yoshihiko

AU - Hoshino, Katsumichi

AU - Nagaoka, Kenichi

AU - Shinohara, Kouji

AU - Fujisawa, Akihide

AU - Uehara, Kazuya

AU - Kusama, Yoshinori

AU - Ida, Katsumi

AU - Yoshimura, Yasuo

AU - Okamura, Shoichi

AU - Matsuoka, Keisuke

AU - Ejiri, Akira

AU - Takase, Yuichi

AU - Itoh, Kimitaka

AU - Yagi, Masatoshi

AU - Itoh, Sanae I.

PY - 2006/1/1

Y1 - 2006/1/1

N2 - This paper presents experimental studies of nonlinear processes between meso-scale structures and turbulent fluctuations, by use of bispectral analysis, in the edge region of toroidal plasmas. In ohmically heated plasmas of the JFT-2Mtokamak, the drift wave-zonal flow system is investigated by observation of the potential fluctuations. The total bicoherence is composed of two components, i.e., the peak at the geodesic acoustic mode (GAM) frequency and broadband distribution. The biphase is also obtained, which indicates the phase angle of coherent interaction between GAM oscillations and broadband fluctuations. Bispectral functions (e.g., magnitude and phase) give an order-of-estimate agreement for the drift wave-zonal flow systems. Bicoherence analysis is also applied to the edge plasmas of the high-confinement mode (H-mode) of the Compact Helical System (CHS). In the case of CHS plasmas, nonlinear couplings in a system composed of coherent global magneto-hydrodynamic (MHD) oscillations and broadband fluctuations (up to hundreds kHz range) have been observed. Bispectral analysis enhances our understanding of the self-regulation systems of various toroidal plasmas in which strong turbulence and meso-scale structures coexist.

AB - This paper presents experimental studies of nonlinear processes between meso-scale structures and turbulent fluctuations, by use of bispectral analysis, in the edge region of toroidal plasmas. In ohmically heated plasmas of the JFT-2Mtokamak, the drift wave-zonal flow system is investigated by observation of the potential fluctuations. The total bicoherence is composed of two components, i.e., the peak at the geodesic acoustic mode (GAM) frequency and broadband distribution. The biphase is also obtained, which indicates the phase angle of coherent interaction between GAM oscillations and broadband fluctuations. Bispectral functions (e.g., magnitude and phase) give an order-of-estimate agreement for the drift wave-zonal flow systems. Bicoherence analysis is also applied to the edge plasmas of the high-confinement mode (H-mode) of the Compact Helical System (CHS). In the case of CHS plasmas, nonlinear couplings in a system composed of coherent global magneto-hydrodynamic (MHD) oscillations and broadband fluctuations (up to hundreds kHz range) have been observed. Bispectral analysis enhances our understanding of the self-regulation systems of various toroidal plasmas in which strong turbulence and meso-scale structures coexist.

UR - http://www.scopus.com/inward/record.url?scp=85034629075&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85034629075&partnerID=8YFLogxK

U2 - 10.1585/pfr.1.041

DO - 10.1585/pfr.1.041

M3 - Article

AN - SCOPUS:85034629075

VL - 1

JO - Plasma and Fusion Research

JF - Plasma and Fusion Research

SN - 1880-6821

M1 - 041

ER -