Ballooning characteristics in density fluctuations observed with the 2 MeV heavy ion beam probe on the TEXT-U tokamak

Fujisawa, A.; Ouroua, A.; Heard, J. W.; Crowley, T. P.; Schoch, P. M.; Connor, K. A.; Hickok, R. L.; Wootton, A. J.

doi:10.1088/0029-5515/36/3/i10

Cited by 31 publications

(20 citation statements)

References 14 publications

(2 reference statements)

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“…iii) Fluctuation asymmetry and configuration geometric effects In toroidal plasmas, the poloidal asymmetry of fluctuation structure has been expected in theories and simulations, and confirmed in experiments [82,83]. Therefore, the plasma turbulence and transport can be dependent on the magnetic field curvature or geodesic curvature.…”

Section: Ii) Competitions Between Fluctuating Structures Of Differentmentioning

confidence: 69%

Experimental studies of mesoscale structure and its interactions with microscale waves in plasma turbulence

Fujisawa

2011

Plasma Phys. Control. Fusion

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The modern view of plasma turbulence has been established due to the discovery of zonal flows and other structures drift-waves generate, and contribute to exploring new manners of understanding of transport and structural formation in magnetized plasmas and astronomic objects. This article presents recent development of laboratory experiments for plasma turbulence to have advanced its understanding and have made the paradigm shift. The topics include the discoveries of mesoscale structures, such as zonal flows and streamers, the recent development of analyzing techniques to quantify the couplings between different scale structures and methods to elucidate energy transfer direction, and turbulence transport and barrier formation. Finally, future experiments are suggested for establishing the first-principle laws of turbulence transport and structural formation.

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Section: Ii) Competitions Between Fluctuating Structures Of Differentmentioning

confidence: 69%

Experimental studies of mesoscale structure and its interactions with microscale waves in plasma turbulence

Fujisawa

2011

Plasma Phys. Control. Fusion

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“…2. Localization of fluctuations in the outside of torus has been observed [73]. A sample of experimental observation on the in-out asymmetry of fluctuations in tokamak is shown in Fig.…”

Section: Early Studies On Localizations Of Turbulence and Transportmentioning

confidence: 89%

“…Localization of turbulence intensity in the outside of torus. Measurements on the TEXT tokamak[73]. Poloidal asymmetry in density fluctuation spectra: (a) sample volume location, (b) power spectra, and (c) coherence between signals from two adjacent sample volumes and the phase difference on the low field side.…”

mentioning

confidence: 99%

Symmetry-Breaking of Turbulence Structure and Position Identification in Toroidal Plasmas

Itoh

Nagashima

et al. 2018

Plasma and Fusion Research

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As a result of the progresses in the study of plasma turbulence, the picture of 'multiple-scale turbulence' is widely accepted, and the 'nonlinear excitation, nonlocal interaction, probabilistic transition' views have been developed. Along the paths of these progresses, importance of new problem, i.e., the symmetry-breaking of turbulence structure (such as up-down asymmetry, excitation of streamer, etc.) is gradually recognized. In this topical review article, we revisit these issues, and illuminate the possibilities that the new progresses (which will be brought about by studying the symmetry-breaking of turbulence) are expected. Examining theoretical predictions and preceding experimental achievements, new advancements, which will be realized, are explained. The experimental study of symmetry-breaking of turbulence structure ultimately requires to measure fluctuations (at all scales) over the whole plasma cross-section simultaneously. In addition, new type of demands can be imposed in measuring of fluctuations over the whole plasma cross-section simultaneously. One of such demands is the accuracy of the measurement position. Problems in this aspect are also discussed. This concise review is used to identify what will be discovered and how it will be reached in future experiments, in the subject of the symmetry-breaking of turbulence structure.

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“…where the poloidal asymmetry of the fluctuations is assumed hence the poloidal angle θ is included. Poloidal asymmetry in turbulence nature has been actually observed in axisymmetric systems such as tokamaks [132]. Therefore, in future the total turbulence-driven fluxes should be evaluated by the integration of the flux in the poloidal direction, considering the poloidal asymmetry of the fluxes.…”

Section: Turbulence and Thermal Structure -Flux Generationmentioning

confidence: 99%

A Review -Observations of Turbulence and Structure in Magnetized Plasmas

Fujisawa

2010

Plasma and Fusion Research

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Magnetized plasma is an non-equilibrium matter rich in nonlinear phenomena; its structural formations are dominated by turbulence. This article provides a brief review of experiments and observations of phenomena occurring in turbulent plasmas, with an emphasis on the methodologies for characterizing turbulence, and visualizing the invisible structure created by turbulence and the internal couplings between the elemental waves that constitute turbulence. Zonal flows, streamers, blobs, and other phenomena are investigated by using analytical methods such as Fourier transformation, wavelet analysis, probabilistic density function analysis, bicoherence, wavelet bicoherence. Finally, the contemporary view of plasma turbulence is presented with discussion of unsolved transport issues in fusion plasmas, such as transport barrier formation and nonlocal transport.

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Ballooning characteristics in density fluctuations observed with the 2 MeV heavy ion beam probe on the TEXT-U tokamak

Cited by 31 publications

References 14 publications

Experimental studies of mesoscale structure and its interactions with microscale waves in plasma turbulence

Experimental studies of mesoscale structure and its interactions with microscale waves in plasma turbulence

Symmetry-Breaking of Turbulence Structure and Position Identification in Toroidal Plasmas

A Review -Observations of Turbulence and Structure in Magnetized Plasmas

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