Multifractality in plasma edge electrostatic turbulence

Neto, Camilo Rodrigues; Guimarães-Filho, Z. O.; Caldas, I. L.; Nascimento, I. C.; Kuznetsov, Yu.K.

doi:10.1063/1.2973175

Cited by 17 publications

(9 citation statements)

References 34 publications

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“…Moreover, the long scale structures are also indicated by the persistence of these signals, characterized by their Hurst exponent, that present a radial profile similar to the radial profile of determinism as shown in Fig. 7 of Reference [40].…”

Section: Recurrence Analysis Of Turbulence Datamentioning

confidence: 74%

Characterizing electrostatic turbulence in tokamak plasmas with high MHD activity

Guimarães-Filho¹,

Lima²,

Caldas³

et al. 2010

J. Phys.: Conf. Ser.

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One of the challenges in obtaining long lasting magnetic confinement of fusion plasmas in tokamaks is to control electrostatic turbulence near the vessel wall. A necessary step towards achieving this goal is to characterize the turbulence level and so as to quantify its effect on the transport of energy and particles of the plasma. In this paper we present experimental results on the characterization of electrostatic turbulence in Tokamak Chauffage Alfvén Brésilien (TCABR), operating in the

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Section: Recurrence Analysis Of Turbulence Datamentioning

confidence: 74%

Characterizing electrostatic turbulence in tokamak plasmas with high MHD activity

Guimarães-Filho¹,

Lima²,

Caldas³

et al. 2010

J. Phys.: Conf. Ser.

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“…In previous work (Domínguez et al, 2017;Lepreti et al, 2004;Nigro et al, 2004;Nigro andCarbone, 2010, 2015;Nigro and Veltri, 2011;Nigro, 2013) the forcing terms were obtained from the Langevin equation…”

Section: Shell Modelmentioning

confidence: 99%

Study of the fractality in a magnetohydrodynamic shell model forced by solar wind fluctuations

Domínguez¹,

Nigro²,

Muñoz³

et al. 2020

Nonlin. Processes Geophys.

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Abstract. The description of the relationship between interplanetary plasma and geomagnetic activity requires complex models. Drastically reducing the ambition of describing this detailed complex interaction and, if we are interested only in the fractality properties of the time series of its characteristic parameters, a magnetohydrodynamic (MHD) shell model forced using solar wind data might provide a possible novel approach. In this paper we study the relation between the activity of the magnetic energy dissipation rate obtained in one such model, which may describe geomagnetic activity, and the fractal dimension of the forcing. In different shell model simulations, the forcing is provided by the solution of a Langevin equation where a white noise is implemented. This forcing, however, has been shown to be unsuitable for describing the solar wind action on the model. Thus, we propose to consider the fluctuations of the product between the velocity and the magnetic field solar wind data as the noise in the Langevin equation, the solution of which provides the forcing in the magnetic field equation. We compare the fractal dimension of the magnetic energy dissipation rate obtained, of the magnetic forcing term, and of the fluctuations of v⋅bz, with the activity of the magnetic energy dissipation rate. We examine the dependence of these fractal dimensions on the solar cycle. We show that all measures of activity have a peak near solar maximum. Moreover, both the fractal dimension computed for the fluctuations of v⋅bz time series and the fractal dimension of the magnetic forcing have a minimum near solar maximum. This suggests that the complexity of the noise term in the Langevin equation may have a strong effect on the activity of the magnetic energy dissipation rate.

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“…These measures are based on the recurrence point density and the diagonal and vertical line structures of the RP. The RQA method is extensively accepted for all types of data analysis in numerous disciplines such as plasma, earth science, finance and economy …”

Section: Introductionmentioning

confidence: 99%

Experimental observation of intermittent route to chaos in magnetized filamentary discharge plasma due to the cylindrical plasma bubble

Megalingam

Sangem

Sarma

2020

Contributions to Plasma Physics

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We delineate an experimental observation of the effect of the magnetic field along with mesh grid biasing in the presence of a cylindrical plasma bubble in a filamentary discharge magnetised plasma system. The cylindrical mesh grid of 80% optical transparency has been negatively biased and introduced in the plasma for creating a plasma bubble. Plasma floating potential fluctuations have been taken outside (LP1) and inside (LP2) of the plasma bubble. It has been noticed that as the external magnetic field is increased the oscillation pattern shows intermittent route to chaos as the system evolved from regular type of relaxation oscillations (of larger amplitude) to an irregular type of oscillations (of smaller amplitude) We have used recurrence quantification analysis (RQA) to the observed intermittency to chaos in the plasma. The main measures of RQA are laminarity (LAM) and determinism (DET). The laminarity measure can be associated with the average time between the chaotic burst in the intermittency. It has also been observed that the DET depends on the control parameter and decreases exponentially, features like a dip in skewness and a hump in the kurtosis with the variation of control parameter have been noticed, which are the strong evidence of intermittent behaviour of the system. Further, a numerical model has been developed to the observed experimental analysis of the intermittent route to chaos. K E Y W O R D Schaos, cylindrical plasma bubble, intermittency

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Multifractality in plasma edge electrostatic turbulence

Cited by 17 publications

References 34 publications

Characterizing electrostatic turbulence in tokamak plasmas with high MHD activity

Characterizing electrostatic turbulence in tokamak plasmas with high MHD activity

Study of the fractality in a magnetohydrodynamic shell model forced by solar wind fluctuations

Experimental observation of intermittent route to chaos in magnetized filamentary discharge plasma due to the cylindrical plasma bubble

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