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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Statistical properties of intermittent bursts in the Texas Helimak

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Author(s):
Pereira, F. A. C. [1] ; Sokolov, I. M. [2, 3] ; Toufen, D. L. [4] ; Guimaraes-Filho, Z. O. [1] ; Caldas, I. L. [1] ; Gentle, K. W. [5, 6]
Total Authors: 6
Affiliation:
[1] Univ Sao Paulo, Inst Phys, BR-05315970 Sao Carlos, SP - Brazil
[2] Humboldt Univ, Inst Phys, D-12489 Berlin - Germany
[3] Humboldt Univ, IRIS Adlershof, D-12489 Berlin - Germany
[4] Fed Inst Educ Sci & Technol Sao Paulo, BR-07115000 Guarulhos, SP - Brazil
[5] Univ Texas Austin, Dept Phys, Austin, TX 78712 - USA
[6] Univ Texas Austin, Inst Fus Studies, Austin, TX 78712 - USA
Total Affiliations: 6
Document type: Journal article
Source: Physics of Plasmas; v. 26, n. 5 MAY 2019.
Web of Science Citations: 0
Abstract

We present investigations of intermittent turbulence in the Texas Helimak, a simple toroidal plasma device in which the turbulence properties are modified by applying a bias voltage. The analyzed turbulence presents high density bursts, detected by Langmuir probes measuring ion saturation current fluctuations. The turbulent time series is reproduced by a synthetic signal model that has bursts with the same temporal profile and random amplitudes, plus a low amplitude fluctuating stochastic background. Using this model, we identify two burst regimes, observed according to the radial position and external bias: in the first regime, the bursts occur in random instants, leading to a Poisson distribution of the time interval between bursts, while in the second regime, the time interval between large bursts is correlated and modeled by a Gamma distribution. Furthermore, we use the shape parameter k that measures the correlation between occurrence times of successive bursts to characterize the burst regime in most of the low field side. We find that in the region described by the second regime, the k values increase with positive applied bias. Published under license by AIP Publishing. (AU)

FAPESP's process: 18/03211-6 - Non linear dynamics
Grantee:Iberê Luiz Caldas
Support type: Research Projects - Thematic Grants
FAPESP's process: 14/07043-0 - Analysis of turbulence and structures propagation on plasma
Grantee:Felipe Augusto Cardoso Pereira
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 15/50122-0 - Dynamic phenomena in complex networks: basics and applications
Grantee:Elbert Einstein Nehrer Macau
Support type: Research Projects - Thematic Grants
FAPESP's process: 17/23128-3 - Turbulence and transport models for the Texas Helimak
Grantee:Felipe Augusto Cardoso Pereira
Support type: Scholarships abroad - Research Internship - Post-doctor