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Spatial inhomogeneity effects on burst temperature estimation using a triple probe configuration in Tokamak Chauffage Alfvén Brésilien tokamak

Part of: Focus on Fusion

Published online by Cambridge University Press:  09 August 2019

W. A. Hernandez Open the ORCID record for W. A. Hernandez [Opens in a new window] ,
Z. O. Guimarães-Filho Open the ORCID record for Z. O. Guimarães-Filho [Opens in a new window] ,
G. G. Grenfell Open the ORCID record for G. G. Grenfell [Opens in a new window]  and
I. C. Nascimento Open the ORCID record for I. C. Nascimento [Opens in a new window]
W. A. Hernandez*
Affiliation:
Institute of Physics, University of São Paulo, São Paulo, São Paulo 05315-970, Brazil Facultad de Ciencias Bàsicas e Ingenierìas, Universidad de los Llanos, Villavicencio 500017, Colombia FiMEB, UAN, Villavicencio 500008, Colombia
Z. O. Guimarães-Filho
Affiliation:
Institute of Physics, University of São Paulo, São Paulo, São Paulo 05315-970, Brazil
G. G. Grenfell
Affiliation:
Institute of Physics, University of São Paulo, São Paulo, São Paulo 05315-970, Brazil Consorzio RFX (CNR, ENEA, INFN, Universit di Padova, Acciaierie Venete SpA), Padova 35127, Italy
I. C. Nascimento
Affiliation:
Institute of Physics, University of São Paulo, São Paulo, São Paulo 05315-970, Brazil
*
†Email address for correspondence: ahernand@if.usp.br
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Abstract

The effects of coherent structures in plasma edge turbulence are an important topic in the study of plasma cross-field transport in magnetically confined plasmas. To properly characterize these structures, their temperature must be measured, which is often done by using Langmuir probes. In this work, the techniques of Langmuir sweep and triple probe are used, considering the effect of plasma sheath expansion in both methods. It is shown that if the sheath expansion is ignored, the triple probe technique gives overestimated temperature values. In addition, the conditional analysis is applied to both techniques in order to evaluate the mean temperature time trace of the coherent structures. It is shown that these time traces can be distorted in the case of the triple probe technique, due to fact that coherent structures destroy the homogeneity condition on the pins array. Therefore, the sweep technique with a conditional selection of points is more suitable than the triple probe to study coherent structures related to bursts, as it performs a local measurement.

Keywords

plasma diagnosticsplasma nonlinear phenomena
Type
Research Article
Information
Journal of Plasma Physics , Volume 85 , Issue 4 , August 2019 , 905850407
Copyright
© Cambridge University Press 2019 

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