Contribution of electrostatic and magnetic turbulence to anomalous transport in tokamak

Miskane, F.; Dezairi, A.; Saifaoui, D.; Imzi, H.; Imrane, H.; Benharraf, M.

doi:10.1051/epjap:2001127

Cited by 5 publications

(11 citation statements)

References 13 publications

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“…Recently, the standard map has been used to model the test particle transport in a tokamak caused by the drift-wave turbulence [50,51]. The more general maps (11) proposed in [9] have been used in [52][53][54] to study stochastic magnetic field lines in tokamaks.…”

Section: Mapping Modelsmentioning

confidence: 99%

On mapping models of field lines in a stochastic magnetic field

Abdullaev¹

2004

Nucl. Fusion

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Mapping models of Hamiltonian systems are discussed using the example of magnetic field lines in magnetically confined fusion plasmas. They are usually constructed in a certain symplectic form by imposing several constraints that make them compatible with a toroidal geometry. The possible symplectic forms of model mappings for Hamiltonian systems are derived using the recently developed method for the construction of symplectic mappings (Abdullaev S.S. 2002 J. Phys. A 35 2811). It is shown that the symplectic mappings may have symmetric and nonsymmetric forms. The generating function of the symmetric mapping depends only on the perturbation field while the one for the nonsymmetric map depends also on the safety factor (or winding number). Mapping models, particularly, a global mapping model in a toroidal system, the tokamap (Balescu R. et al 1998 Phys. Rev. E 58 951), usually used in plasma physics are reviewed and their relations with continuous Hamiltonian systems are discussed. The symmetric form of the tokamap is proposed and compared with the conventional tokamap. The symmetric and nonsymmetric mapping models for field lines in ergodic divertor tokamaks are also considered. It is shown that symmetric mappings closely describe original Hamiltonian systems in comparison with nonsymmetric mappings.

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Section: Mapping Modelsmentioning

confidence: 99%

On mapping models of field lines in a stochastic magnetic field

Abdullaev¹

2004

Nucl. Fusion

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“…To evaluate the plasma particle diffusion [1,[3][4][5][6][7][8][9][10] through the magnetic surfaces within the tokamak reactors, we simulated the particulate diffusion coefficients in two cases. We used the classic formula…”

Section: The Diffusion Of the Particlesmentioning

confidence: 99%

Transport barriers with magnetic shear in a tokamak

Mouden¹,

Saifaoui²,

Dezairi

et al. 2007

J. Plasma Phys.

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The reversed magnetic shear is the most important factor in the study of the plasmas of a tokamak. In this paper we focus our research, as a first stage, on the control of the improved confinement regimes by studying the influence of the reversed shear on its quality in the plasma of a tokamak and especially in reducing the anomalous transport in ITER. Then we study the influence of the perturbation modes on the particle diffusion. At the end, a comparison between simulation results obtained using ITER and TEXT parameters is carried out.

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“…These models are widely used to study the particle transport caused by turbulent fields in fusion plasmas (see, e.g., Refs. [26][27][28][29][30][31][32][33][34][35] and references therein) and the transport cosmic rays in heliosphere (see Refs. [7,36,37] and references therein).…”

Section: Introductionmentioning

confidence: 99%

“…Particularly, in Refs. [27,28,32,33] the test particle models are used to explore the effect of low and reversed magnetic shear on the radial transport of field lines and particles in the presence of magnetic and electrostatic perturbations.…”

Section: Introductionmentioning

confidence: 99%

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Chaotic transport in Hamiltonian systems perturbed by a weak turbulent wave field

Abdullaev

2011

Phys. Rev. E

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Chaotic transport in a Hamiltonian system perturbed by a weak turbulent wave field is studied. It is assumed that a turbulent wave field has a wide spectrum containing up to thousands of modes whose phases are fluctuating in time with a finite correlation time. To integrate the Hamiltonian equations a fast symplectic mapping is derived. It has a large time-step equal to one full turn in angle variable. It is found that the chaotic transport across tori caused by the interactions of small-scale resonances have a fractal-like structure with the reduced or zero values of diffusion coefficients near low-order rational tori thereby forming transport barriers there. The density of rational tori is numerically calculated and its properties are investigated. It is shown that the transport barriers are formed in the gaps of the density of rational tori near the low-order rational tori. The dependencies of the depth and width of transport barriers on the wave field spectrum and the correlation time of fluctuating turbulent field (or the Kubo number) are studied. These numerical findings may have importance in understanding the mechanisms of transport barrier formation in fusion plasmas.

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Contribution of electrostatic and magnetic turbulence to anomalous transport in tokamak

Cited by 5 publications

References 13 publications

On mapping models of field lines in a stochastic magnetic field

On mapping models of field lines in a stochastic magnetic field

Transport barriers with magnetic shear in a tokamak

Chaotic transport in Hamiltonian systems perturbed by a weak turbulent wave field

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