The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Yannick Marandet - One of the best experts on this subject based on the ideXlab platform.
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Effect of turbulent fluctuations on Neutral Particles transport with the TOKAM3X-EIRENE turbulence code
Nuclear materials and energy, 2018Co-Authors: Yannick Marandet, Patrick Tamain, Hugo Bufferand, Ph. Ghendrih, G. Ciraolo, Eric SerreAbstract:Abstract The effect of turbulent fluctuations on the transport of Neutral Particles (atoms, molecules) in tokamak plasmas is investigated with the 3D global turbulence code TOKAM3X-EIRENE in limiter geometry. The statistical properties of turbulent fields relevant to this work are discussed, including the recycling flux. The Neutral particle transport is recalculated on the mean field plasma, and compared to the mean Neutral particle density/flows obtained from the turbulent simulation, so as to assess the effects of the fluctuations, in particular on the ionization balance. The latter effects are remarkably modest in the simulation presented here, but are expected to become more and more pronounced as the high recycling regime is approached, in particular because the plasma temperature becomes low enough so that ionization is strongly non-linear. However, the turbulent fluctuations in the SOL do have a substantial effect on the Neutral densities on the low field side of the limiter, including in the confined plasma. These effects are traced back to non-linearities in the plasma flux at the wall, and the fluctuations in the latter are identified as an important contributor both to Neutral particle density fluctuations and to deviations from mean Neutral particle density/flows in the turbulent simulation with respect to the same quantities recalculated on the mean plasma fields.
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Influence of Neutral Particles on scrape-off layer turbulence with ă application to the interpretation of fast camera data
Journal of Nuclear Materials, 2013Co-Authors: Yannick Marandet, P. Genesio, Patrick Tamain, Romain Futtersack, Philippe Ghendrih, Hugo Bufferand, A. MekkaouiAbstract:The role of Neutral Particles (atoms, molecules) on scrape-off layer turbulence is investigated using a 2D interchange model. This work is a first step towards a synthetic diagnostic for Gas Puff Imaging experiments, where gas is injected to visualize turbulent structures. A simple Neutral model is used to identify various limiting cases of interest. Too strong puffing leads to a reduction of the turbulence fluctuation level. In the strong interaction regime, where the Neutral density fluctuates, the relationship between plasma density maps and synthetic camera pictures is discussed. The EIRENE Monte Carlo code has been coupled to TOKAM2D, and a first study of the effect of the Monte Carlo noise on statistical properties of turbulence is presented. (C) 2013 Elsevier B.V. All rights reserved.
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A coarse-grained transport model for Neutral Particles in turbulent plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Detlev Reiter, Yannick Marandet, P. Boerner, P. Genesio, J. Rosato, H. Capes, M. Koubiti, L. Godbert-mouret, Roland StammAbstract:The transport of Neutral Particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transport models which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average Neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for Neutral Particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D2 molecules and beryllium atoms. The sensitivity of our results to the...
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A Coarse-grained Kinetic Equation for Neutral Particles in Turbulent Fusion Plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Yannick Marandet, D. Reiter, P. Boerner, Fabrice Catoire, P. Genesio, J. Rosato, Roland Stamm, H. Capes, M. KoubitiAbstract:A coarse-grained kinetic equation for Neutral Particles (atoms, molecules) in magnetized fusion plasmas, valid on time scales large compared to the turbulence correlation time, is presented. This equation includes the effects of plasma density fluctuations, described by Gamma statistics, on the transport of Neutral Particles. These effects have so far been neglected in plasma edge modeling, in spite of the fact that the amplitude of fluctuations can be of order unity. Density fluctuations are shown to have a marked effect on the screening of Neutrals and on the spatial localization of the ionization source, in particular at high density. The coarse-grained equations obtained in this work are readily implemented in edge code suites currently used for fusion plasma analysis and future divertor design (ITER, DEMO).
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A coarse-grained transport model for Neutral Particles in turbulent plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Yannick Marandet, D. Reiter, P. Boerner, P. Genesio, J. Rosato, H. Capes, M. Koubiti, L. Godbert-mouret, Roland StammAbstract:The transport of Neutral Particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transportmodels which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average Neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for Neutral Particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D2 molecules and beryllium atoms. The sensitivity of our results to the assumptions on the statistical properties of fluctuations is investigated.
A. Mekkaoui - One of the best experts on this subject based on the ideXlab platform.
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Influence of Neutral Particles on scrape-off layer turbulence with ă application to the interpretation of fast camera data
Journal of Nuclear Materials, 2013Co-Authors: Yannick Marandet, P. Genesio, Patrick Tamain, Romain Futtersack, Philippe Ghendrih, Hugo Bufferand, A. MekkaouiAbstract:The role of Neutral Particles (atoms, molecules) on scrape-off layer turbulence is investigated using a 2D interchange model. This work is a first step towards a synthetic diagnostic for Gas Puff Imaging experiments, where gas is injected to visualize turbulent structures. A simple Neutral model is used to identify various limiting cases of interest. Too strong puffing leads to a reduction of the turbulence fluctuation level. In the strong interaction regime, where the Neutral density fluctuates, the relationship between plasma density maps and synthetic camera pictures is discussed. The EIRENE Monte Carlo code has been coupled to TOKAM2D, and a first study of the effect of the Monte Carlo noise on statistical properties of turbulence is presented. (C) 2013 Elsevier B.V. All rights reserved.
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A coarse-grained transport model for Neutral Particles in turbulent plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Detlev Reiter, Yannick Marandet, P. Boerner, P. Genesio, J. Rosato, H. Capes, M. Koubiti, L. Godbert-mouret, Roland StammAbstract:The transport of Neutral Particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transport models which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average Neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for Neutral Particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D2 molecules and beryllium atoms. The sensitivity of our results to the...
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A Coarse-grained Kinetic Equation for Neutral Particles in Turbulent Fusion Plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Yannick Marandet, D. Reiter, P. Boerner, Fabrice Catoire, P. Genesio, J. Rosato, Roland Stamm, H. Capes, M. KoubitiAbstract:A coarse-grained kinetic equation for Neutral Particles (atoms, molecules) in magnetized fusion plasmas, valid on time scales large compared to the turbulence correlation time, is presented. This equation includes the effects of plasma density fluctuations, described by Gamma statistics, on the transport of Neutral Particles. These effects have so far been neglected in plasma edge modeling, in spite of the fact that the amplitude of fluctuations can be of order unity. Density fluctuations are shown to have a marked effect on the screening of Neutrals and on the spatial localization of the ionization source, in particular at high density. The coarse-grained equations obtained in this work are readily implemented in edge code suites currently used for fusion plasma analysis and future divertor design (ITER, DEMO).
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A coarse-grained transport model for Neutral Particles in turbulent plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Yannick Marandet, D. Reiter, P. Boerner, P. Genesio, J. Rosato, H. Capes, M. Koubiti, L. Godbert-mouret, Roland StammAbstract:The transport of Neutral Particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transportmodels which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average Neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for Neutral Particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D2 molecules and beryllium atoms. The sensitivity of our results to the assumptions on the statistical properties of fluctuations is investigated.
Eric Serre - One of the best experts on this subject based on the ideXlab platform.
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Effect of turbulent fluctuations on Neutral Particles transport with the TOKAM3X-EIRENE turbulence code
Nuclear materials and energy, 2018Co-Authors: Yannick Marandet, Patrick Tamain, Hugo Bufferand, Ph. Ghendrih, G. Ciraolo, Eric SerreAbstract:Abstract The effect of turbulent fluctuations on the transport of Neutral Particles (atoms, molecules) in tokamak plasmas is investigated with the 3D global turbulence code TOKAM3X-EIRENE in limiter geometry. The statistical properties of turbulent fields relevant to this work are discussed, including the recycling flux. The Neutral particle transport is recalculated on the mean field plasma, and compared to the mean Neutral particle density/flows obtained from the turbulent simulation, so as to assess the effects of the fluctuations, in particular on the ionization balance. The latter effects are remarkably modest in the simulation presented here, but are expected to become more and more pronounced as the high recycling regime is approached, in particular because the plasma temperature becomes low enough so that ionization is strongly non-linear. However, the turbulent fluctuations in the SOL do have a substantial effect on the Neutral densities on the low field side of the limiter, including in the confined plasma. These effects are traced back to non-linearities in the plasma flux at the wall, and the fluctuations in the latter are identified as an important contributor both to Neutral particle density fluctuations and to deviations from mean Neutral particle density/flows in the turbulent simulation with respect to the same quantities recalculated on the mean plasma fields.
Roland Stamm - One of the best experts on this subject based on the ideXlab platform.
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A coarse-grained transport model for Neutral Particles in turbulent plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Detlev Reiter, Yannick Marandet, P. Boerner, P. Genesio, J. Rosato, H. Capes, M. Koubiti, L. Godbert-mouret, Roland StammAbstract:The transport of Neutral Particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transport models which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average Neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for Neutral Particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D2 molecules and beryllium atoms. The sensitivity of our results to the...
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A Coarse-grained Kinetic Equation for Neutral Particles in Turbulent Fusion Plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Yannick Marandet, D. Reiter, P. Boerner, Fabrice Catoire, P. Genesio, J. Rosato, Roland Stamm, H. Capes, M. KoubitiAbstract:A coarse-grained kinetic equation for Neutral Particles (atoms, molecules) in magnetized fusion plasmas, valid on time scales large compared to the turbulence correlation time, is presented. This equation includes the effects of plasma density fluctuations, described by Gamma statistics, on the transport of Neutral Particles. These effects have so far been neglected in plasma edge modeling, in spite of the fact that the amplitude of fluctuations can be of order unity. Density fluctuations are shown to have a marked effect on the screening of Neutrals and on the spatial localization of the ionization source, in particular at high density. The coarse-grained equations obtained in this work are readily implemented in edge code suites currently used for fusion plasma analysis and future divertor design (ITER, DEMO).
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A coarse-grained transport model for Neutral Particles in turbulent plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Yannick Marandet, D. Reiter, P. Boerner, P. Genesio, J. Rosato, H. Capes, M. Koubiti, L. Godbert-mouret, Roland StammAbstract:The transport of Neutral Particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transportmodels which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average Neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for Neutral Particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D2 molecules and beryllium atoms. The sensitivity of our results to the assumptions on the statistical properties of fluctuations is investigated.
M. Koubiti - One of the best experts on this subject based on the ideXlab platform.
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A coarse-grained transport model for Neutral Particles in turbulent plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Detlev Reiter, Yannick Marandet, P. Boerner, P. Genesio, J. Rosato, H. Capes, M. Koubiti, L. Godbert-mouret, Roland StammAbstract:The transport of Neutral Particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transport models which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average Neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for Neutral Particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D2 molecules and beryllium atoms. The sensitivity of our results to the...
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A Coarse-grained Kinetic Equation for Neutral Particles in Turbulent Fusion Plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Yannick Marandet, D. Reiter, P. Boerner, Fabrice Catoire, P. Genesio, J. Rosato, Roland Stamm, H. Capes, M. KoubitiAbstract:A coarse-grained kinetic equation for Neutral Particles (atoms, molecules) in magnetized fusion plasmas, valid on time scales large compared to the turbulence correlation time, is presented. This equation includes the effects of plasma density fluctuations, described by Gamma statistics, on the transport of Neutral Particles. These effects have so far been neglected in plasma edge modeling, in spite of the fact that the amplitude of fluctuations can be of order unity. Density fluctuations are shown to have a marked effect on the screening of Neutrals and on the spatial localization of the ionization source, in particular at high density. The coarse-grained equations obtained in this work are readily implemented in edge code suites currently used for fusion plasma analysis and future divertor design (ITER, DEMO).
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A coarse-grained transport model for Neutral Particles in turbulent plasmas
Physics of Plasmas, 2012Co-Authors: A. Mekkaoui, Yannick Marandet, D. Reiter, P. Boerner, P. Genesio, J. Rosato, H. Capes, M. Koubiti, L. Godbert-mouret, Roland StammAbstract:The transport of Neutral Particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transportmodels which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average Neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for Neutral Particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D2 molecules and beryllium atoms. The sensitivity of our results to the assumptions on the statistical properties of fluctuations is investigated.