Auswahl der wissenschaftlichen Literatur zum Thema „Transport néoclassique“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Inhaltsverzeichnis
Machen Sie sich mit den Listen der aktuellen Artikel, Bücher, Dissertationen, Berichten und anderer wissenschaftlichen Quellen zum Thema "Transport néoclassique" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Zeitschriftenartikel zum Thema "Transport néoclassique"
Delisle, Pascal. „Circulation routière et nuisances environnementales Quelle place pour l'analyse économique ?“ Revue de l'OFCE 59, Nr. 4 (01.11.1996): 135–66. http://dx.doi.org/10.3917/reof.p1996.59n1.0135.
Der volle Inhalt der QuelleDissertationen zum Thema "Transport néoclassique"
Estève, Damien. „Etude gyrocinétique du transport multi-espèces néoclassique et turbulent dans un plasma de fusion“. Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4107.
Der volle Inhalt der QuelleTokamaks aim at producing energy out of Deuterium-Tritium fusion reactions. Impurity degrade performance by diluting the D-T fuel and radiating. They originate from D-T reactions (Helium), or from edge seeding and plasma-wall interaction. In ITER the divertor will be in Tungsten (W). JET and ASDEX-Upgrade experiments have shown that W can penetrate up to the core and lead to radiative collapses. Understanding, predicting and possibly controlling its transport is therefore mandatory. Both collisions and turbulence contribute to impurity transport. In the tokamak magnetic topology, collisions lead to neoclassical transport. So far, these two transport channels are modelled separately, assuming additivity of the fluxes. We have addressed this critical issue by means of 5D gyrokinetic (GK) simulations with the GYSELA code. We have derived a new multi-species GK collision operator, valid for any trace and thermal impurity. The implemented reduced version, adapted to the high performance computing constraints of GYSELA, verifies the conservation properties of elastic collisions and the neoclassical theory. The diffusion coefficient and pinch velocity agree with the predictions in all collisionality regimes. Thermal screening is also recovered for W, although not at the expected magnitude - in link to isotropy and stationarity assumptions. Self-consistent simulations reveal synergies between neoclassical and turbulent transports: the total flux of W differs by up to a factor 2 from the sum of the two, obtained from separate simulations. This is partly due to the modification – magnitude and radial structure – by turbulence of the m=1 poloidal mode of the electric potential
Abiteboul, Jérémie. „Transport turbulent et néoclassique de quantité de mouvement toroïdale dans les plasmas de tokamak“. Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4062/document.
Der volle Inhalt der QuelleThe goal of magnetic confinement devices such as tokamaks is to produce energy from nuclear fusion reactions in plasmas at low densities and high temperatures. Experimentally, toroidal flows have been found to significantly improve the energy confinement, and therefore the performance of the machine. As extrinsic momentum sources will be limited in future fusion devices such as ITER, an understanding of the physics of toroidal momentum transport and the generation of intrinsic toroidal rotation in tokamaks would be an important step in order to predict the rotation profile in experiments. Among the mechanisms expected to contribute to the generation of toroidal rotation is the transport of momentum by electrostatic turbulence, which governs heat transport in tokamaks. Due to the low collisionality of the plasma, kinetic modeling is mandatory for the study of tokamak turbulence. In principle, this implies the modeling of a six-dimensional distribution function representing the density of particles in position and velocity phase-space, which can be reduced to five dimensions when considering only frequencies below the particle cyclotron frequency. This approximation, relevant for the study of turbulence in tokamaks, leads to the so-called gyrokinetic model and brings the computational cost of the model within the presently available numerical resources. In this work, we study the transport of toroidal momentum in tokamaks in the framework of the gyrokinetic model
Abiteboul, Jeremie. „Transport turbulent et néoclassique de quantité de mouvement toroïdale dans les plasmas de tokamak“. Phd thesis, Aix-Marseille Université, 2012. http://tel.archives-ouvertes.fr/tel-00777996.
Der volle Inhalt der QuelleDonnel, Peter. „Impurity transport in tokamak plasmas : gyrokinetic study of neoclassical and turbulent transport“. Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0485/document.
Der volle Inhalt der QuelleImpurity transport is an issue of utmost importance for tokamaks. Indeed high-Z materials are only partially ionized in the plasma core, so that they can lead to prohibitive radiative losses even at low concentrations, and impact dramatically plasma performance and stability. On-axis accumulation of tungsten has been widely observed in tokamaks.While the very core impurity peaking is generally attributed to neoclassical effects, turbulent transport could well dominate in the gradient region at ITER relevant collisionality. Up to recently, first principles simulations of corresponding fluxes were performed with different dedicated codes, implicitly assuming that both transport channels are separable and therefore additive. The validity of this assumption is questionned. Simulations obtained with the gyrokinetic code GYSELA have shown clear evidences of a neoclassical-turbulence synergy for impurity transport and allowed the identification of a mechanism that underly this synergy.An analytical work allows to compute the level and the structure of the axisymmetric part of the electric potential knowing the turbulence intensity. Two mechanisms are found for the generation of poloidal asymmetries of the electric potential: flow compressibility and the ballooning of the turbulence. A new prediction for the neoclassical impurity flux in presence of large poloidal asymmetries and pressure anisotropies has been derived. A fair agreement has been found between the new theoretical prediction for neoclassical impurity flux and the results of a GYSELA simulation displaying large poloidal asymmetries and pressure anisotropies induced by the presence of turbulence
Donnel, Peter. „Impurity transport in tokamak plasmas : gyrokinetic study of neoclassical and turbulent transport“. Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0485.
Der volle Inhalt der QuelleImpurity transport is an issue of utmost importance for tokamaks. Indeed high-Z materials are only partially ionized in the plasma core, so that they can lead to prohibitive radiative losses even at low concentrations, and impact dramatically plasma performance and stability. On-axis accumulation of tungsten has been widely observed in tokamaks.While the very core impurity peaking is generally attributed to neoclassical effects, turbulent transport could well dominate in the gradient region at ITER relevant collisionality. Up to recently, first principles simulations of corresponding fluxes were performed with different dedicated codes, implicitly assuming that both transport channels are separable and therefore additive. The validity of this assumption is questionned. Simulations obtained with the gyrokinetic code GYSELA have shown clear evidences of a neoclassical-turbulence synergy for impurity transport and allowed the identification of a mechanism that underly this synergy.An analytical work allows to compute the level and the structure of the axisymmetric part of the electric potential knowing the turbulence intensity. Two mechanisms are found for the generation of poloidal asymmetries of the electric potential: flow compressibility and the ballooning of the turbulence. A new prediction for the neoclassical impurity flux in presence of large poloidal asymmetries and pressure anisotropies has been derived. A fair agreement has been found between the new theoretical prediction for neoclassical impurity flux and the results of a GYSELA simulation displaying large poloidal asymmetries and pressure anisotropies induced by the presence of turbulence
Lim, Kyungtak. „Transport d’impuretés dans les plasmas de fusion et impact sur le confinement global“. Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0186.
Der volle Inhalt der QuelleThe energy of stars and the Sun in particular comes from nuclear fusion. At the center of the Sun, the temperature reached is 15 million degrees. With such a temperature, electrons are released from the nuclei, generating a plasma. The behavior of plasma is particularly complex since each particle is influenced by long-range interactions with all other particles. Plasma physics seeks to describe the evolution and behavior of such systems. In nuclear fusion, the inevitable presence of impurities is closely related to the fusion itself, to the presence of walls. A thorough understanding of the transport of impurities is crucial for the realization of the ITER project. During a plasma discharge, various impurities may be present simultaneously, for example, helium (He) as a reactant in the Deuterium (D)-Tritium (T) fusion reactions, argon (Ar) or nitrogen (Ni) which may be injected voluntarily to reduce the heat flux on the divertor, and heavy impurities - carbon (C) and tungsten (W) - from plasma-wall interactions. It is now well known that the accumulation of heavy impurities in the plasma core can cause a drop in reactor performance by diluting the main DT fuel and radiating energy. There are three different mechanisms by which impurity transport is generated: (i) turbulence, (ii) collisional effects (neoclassical transport), and (iii) MHD instabilities. During this thesis, we have limited ourselves to the electrostatic case, thus only the first two mechanisms have been studied numerically and therapeutically.In this manuscript, we have studied the turbulent and neoclassical transport of impurities in different configurations. The overall results obtained throughout this manuscript imply that heavy impurities tend to accumulate in the central region and are very sensitive to external conditions. Fortunately, it appears that appropriate use of an ion cyclotron resonance heating (ICRH) system can mitigate tungsten accumulation in the core by reducing poloidal asymmetry and increasing turbulent outward flow. The application of the ICRH heating system in GYSELA remains a future work