K.L. van de Plassche J. Citrin C. Bourdelle Y. Camenen F. J. Casson V.I. Dagnelie F. Felici A. Ho JET Contributors
We present an ultrafast neural network (NN) turbulent tokamak transport model, QLKNN, for heat and particle fluxes. QLKNN is a surrogate model based on a database of 3 · 108 flux calculations of the quasilinear gyrokinetic transport model QuaLiKiz. To ensure accurate reproduction of the underlying model, we include known features of the…
Preprint PublishedM Marin J Citrin C Bourdelle Y Camenen F J Casson A Ho F Koechl M Maslov JET Contributors
Core turbulent particle transport with multiple isotopes can display observable differences in behaviour between the electron and ion particle channels. Experimental observations at JET with mixed H-D plasmas and varying NBI and gas-puff sources [M. Maslov et al., Nucl. Fusion 7 076022 (2018)] inferred source dominated electr…
Preprint PublishedS. Breton F.J. Casson C. Bourdelle J. Citrin Y. Baranov Y. Camenen C. Challis J. Garcia G. Corrigan L. Garzotti S. Henderson F. Koechl M. OMullane T. Puetterich M. Sertoli M. Valisa JET contributors
For the first time, over five confinement times, the self-consistent flux driven time evolution of heat, momentum transport and particle fluxes of electrons and multiple ions including Tungsten (W) is modeled within the integrated modeling platform JETTO [Romanelli M et al PFR 2014], using first principle-based codes : namely, QuaLiKiz [Bourd…
Preprint PublishedC. Bourdelle Y. Camenen J. Citrin M. Marin F.J. Casson F. Koechl M. Maslov
In Ion-Temperature-Gradient (ITG) driven turbulence, the resonance condition leads to ion particle turbulent transport coefficients significantly larger than electron particle turbulent transport coefficients. This is shown in non-linear gyrokinetic simulations and explained by an analytical quasilinear model. It is then illustrated by JETTO-QuaLi…
Preprint PublishedP. Manas Y. Camenen S. Benkadda H. Weisen C. Angioni F.J. Casson C. Giroud M. Gelfusa M. Maslov JET contributors
Quantitative comparisons are presented between gyrokinetic simulations and experimental values of the carbon impurity peaking factor in a database of JET H-modes during the carbon wall era. These plasmas feature strong NBI heating, hence high values of toroidal rotation and correponding gradient. Furthermore, the carbon profiles present particularl…
Preprint PublishedS. Breton F.J. Casson C. Bourdelle C. Angioni E. Belli Y. Camenen J. Citrin X. Garbet Y. Sarazin The JET contributors
Heavy impurities, such as tungsten (W), can exhibit strongly poloidally asymmetric density profiles in rotating or radio frequency heated plasmas. In the metallic environment of JET, the poloidal asymmetry of tungsten enhances its neoclassical transport up to an order of magnitude, so that neoclassical convection is expected to dominate over turbul…
PreprintA.G. Peeters F. Rath R. Buchholz Y. Camenen J. Candy F.J. Casson S.R. Grosshauser W.A. Hornsby D. Strintzi A. Weikl
It is shown that ITG turbulence close to the threshold exhibits a long time behaviour, with smaller heat fluxes at later times. This reduction is connected with the slow growth of long wave length zonal flows and, consequently, the numerical dissipation on these flows must be sufficient small. Close to the nonlinear threshold for turbulence generat…
Preprint PublishedY. Camenen F.J. Casson P. Manas A.G. Peeters
The interplay between toroidal rotation u, parallel flow shear u? and perpendicular flow shear ?E in the stabilisation of tokamak turbulence is investigated in non-linear flux-tube gyrokinetic simulations with the GKW code. The non-linear simulations are performed for a reference L-mode DIII-D plasma (the so-called shortfall case) at r/a = 0.8, var…
Preprint PublishedG. Merlo O. Sauter S. Brunner A. Burckel Y. Camenen F. Casson W.Dorland E. Fable T. Görler F. Jenko D. Told A. Peeters L. Villard
Verification is the fundamental step that any turbulence simulation code has to be submitted in order to assess the proper implementation of the underlying equations. We have carried out a cross comparison of three flux tube gyrokinetic codes, GENE [F. Jenko et al., Phys. Plasmas 7, 1904 (2000)], GKW [A. G. Peeters et al., Comput. Phys. Commun. 180…
Preprint PublishedG. Szepesi M. Romanelli F. Militello A.G. Peeters Y. Camenen F.J. Casson W.A. Hornsby A.P. Snodin D. Wagner The Ftu Team
The impact of lithium impurities on the microstability and turbulent transport characteristics in the core of a typical FTU Liquid Lithium Limiter (LLL) (Mazzitelli et al., Nucl. Fusion, 2011) discharge during the density ramp-up phase is studied. A non-linear gyrokinetic analysis performed with GKW (Peeters et al., Comp. Phys. Comm., 2009) accompa…
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