Scrape-off layer intermittency in the Castor tokamak

Heller, M. V. A. P.; Brasilio, Z A; Caldas, Iberê L.; Ştöckel, J.; Petrzilka, J.

doi:10.1063/1.873324

Cited by 46 publications

(36 citation statements)

References 20 publications

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“…The very meaning of profiles could also be questioned. This first principle description of a complex cross-field transport is also backed by recent experimental evidence of long range transport in the SOL [58,128,77,82], and intermittent transport events in the SOL [89,575,93,576,49,87,86].…”

Section: Impurity Modellingmentioning

confidence: 99%

“…It should be noted that while non-Gaussian PDFs, intermittency, and motion of coherent structures has been well documented over a number of years [88,89,90,91,92,93,94,95,96,97], clear connections to a rapid cross-field transport mechanism in the far SOL and the potential impact on tokamak reactor operation have only recently been widely recognized.…”

Section: Particle Transport In the Solmentioning

confidence: 99%

See 1 more Smart Citation

Chapter 4: Power and particle control

Divertor¹,

Database²,

Editors³

1999

Nucl. Fusion

282

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Abstract.Progress, since the ITER Physics Basis publication, in understanding the processes that will determine the properties of the plasma edge and its interaction with material elements in ITER is described. Experimental areas where significant progress has taken place are : energy transport in the SOL in particular of the anomalous transport scaling, particle transport in the SOL that plays a major role in the interaction of diverted plasmas with the main chamber material elements, ELM energy deposition on material elements and the transport mechanism for the ELM energy from the main plasma to the plasma facing components, the physics of plasma detachment and neutral dynamics including the edge density profile structure and the control of plasma particle content and He removal, the erosion of low and high Z materials in fusion devices, their transport to the core plasma and their migration at the plasma edge including the formation of mixed materials, the processes determining the size and location of the retention of tritium in fusion devices and methods to remove it and the processes determining the efficiency of the various fuelling methods as well as their development towards the ITER requirements. This experimental progress has been accompanied by the development of modelling tools for the physical processes at the edge plasma and plasma-materials interaction and the further validation of these models by comparing their predictions with the new experimental results. Progress in the modelling development and validation has been mostly concentrated in the following areas : refinement of the predictions for ITER with plasma edge modelling codes by inclusion of detailed geometrical features of the divertor and the introduction of physical effects, which can play a 2 major role in determining the divertor parameters at the divertor for ITER conditions such as hydrogen radiation transport and neutral-neutral collisions, modelling of the ion orbits at the plasma edge, which can play a role in determining power deposition at the divertor target, models for plasma-materials and plasma dynamics interaction during ELMs and disruptions, models for the transport of impurities at the plasma edge to describe the core contamination by impurities and the migration of eroded materials at the edge plasma and its associated tritium retention and models for the turbulent processes that determine the anomalous transport of energy and particles across the SOL. The implications for the expected performance of the reference regimes in ITER, the operation of the ITER device and the lifetime of the plasma facing materials are discussed. Introduction.This chapter outlines the significant progress achieved since the ITER Physics Basis in understanding basic scrape-off layer (SOL) and divertor processes in a tokamak. The interaction of plasma with first-wall surfaces will have considerable impact on the performance of fusion plasmas, the lifetime of plasma facing components, and the retention of tritium in next step Burning Plasma E...

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Section: Impurity Modellingmentioning

confidence: 99%

Section: Particle Transport In the Solmentioning

confidence: 99%

Chapter 4: Power and particle control

Divertor¹,

Database²,

Editors³

1999

Nucl. Fusion

282

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“…Wavelet analysis has been used to evaluate the blob size, lifetime, local intermittency measure, packing fraction, linear density of structures, and bicoherence in various devices. 22,126,144,150,152,164,171,177,178,180,189,191,218 Statistical analyses have searched for self-organized criticality or 'avalanche'-like behavior using techniques such as the waiting time distribution, self-similarity, and Hurst exponents. 125,151,173,187,226,237 The fractal structure was investigated in HYBTOK-II, T-10, LHD, and NAGDIS-II, 178,238,239 and the singular value (or proper or biorthogonal) decomposition technique was used to identify blob structures.…”

Section: Analysis Techniquesmentioning

confidence: 99%

Convective transport by intermittent blob-filaments: Comparison of theory and experiment

2011

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A blob-filament (or simply “blob”) is a magnetic-field-aligned plasma structure which is considerably denser than the surrounding background plasma and highly localized in the directions perpendicular to the equilibrium magnetic field B. In experiments and simulations, these intermittent filaments are often formed near the boundary between open and closed field lines, and seem to arise in theory from the saturation process for the dominant edge instabilities and turbulence. Blobs become charge-polarized under the action of an external force which causes unequal drifts on ions and electrons; the resulting polarization-induced E × B drift moves the blobs radially outwards across the scrape-off-layer (SOL). Since confined plasmas generally are subject to radial or outwards expansion forces (e.g., curvature and ∇B forces in toroidal plasmas), blob transport is a general phenomenon occurring in nearly all plasmas. This paper reviews the relationship between the experimental and theoretical results on blob formation, dynamics and transport and assesses the degree to which blob theory and simulations can be compared and validated against experiments.

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“…Important applications, other than given in the introduction, are the analysis of Neoclassical Tearing Modes [30], and nonlinear phenomena and intermittency in plasma turbulence have been analyzed with a wavelet bi-coherence [31,32].…”

Section: Waveletsmentioning

confidence: 99%