Next projects B review : October 15 2017. Proposal must be submitted before September 30 2017.
Publications and communications which have benefited of mésocentre resources should contain : « This work was granted access to the HPC resources of Aix-Marseille Université financed by the project Equip@Meso (ANR-10-EQPX-29-01) of the program « Investissements d’Avenir » supervised by the Agence Nationale de la Recherche.»
Recent publications :
2017 |
| Simon Cabanes, Jonathan Aurnou, Benjamin Favier & Michael Le Bars (2017): A laboratory model for deep-seated jets on the gas giants. In: Nature Physics, 2017. (Type: Journal Article | Abstract | Links | BibTeX) @article{Cabanes2017, title = {A laboratory model for deep-seated jets on the gas giants}, author = {Simon Cabanes, Jonathan Aurnou, Benjamin Favier & Michael Le Bars}, editor = {Nature Physics}, url = {http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys4001.html}, doi = {10.1038/nphys4001}, year = {2017}, date = {2017-01-23}, journal = {Nature Physics}, abstract = {The strong east–west jet flows on the gas giants, Jupiter1 and Saturn2, have persisted for hundreds of years. Yet, experimental studies cannot reach the planetary regime and similarly strong and quasi-steady jets have been reproduced in numerical models only under simplifying assumptions and limitations. Two models have been proposed: a shallow model where jets are confined to the weather layer and a deep model where the jets extend into the planetary molecular envelope. Here we show that turbulent laboratory flows naturally generate multiple, alternating jets in a rapidly rotating cylindrical container. The observed properties of gas giants’ jets are only now reproduced in a laboratory experiment emulating the deep model. Our findings demonstrate that long-lived jets can persist at high latitudes even under conditions including viscous dissipation and friction and bear relevance to the shallow versus deep models debate in the context of the ongoing Juno mission.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The strong east–west jet flows on the gas giants, Jupiter1 and Saturn2, have persisted for hundreds of years. Yet, experimental studies cannot reach the planetary regime and similarly strong and quasi-steady jets have been reproduced in numerical models only under simplifying assumptions and limitations. Two models have been proposed: a shallow model where jets are confined to the weather layer and a deep model where the jets extend into the planetary molecular envelope. Here we show that turbulent laboratory flows naturally generate multiple, alternating jets in a rapidly rotating cylindrical container. The observed properties of gas giants’ jets are only now reproduced in a laboratory experiment emulating the deep model. Our findings demonstrate that long-lived jets can persist at high latitudes even under conditions including viscous dissipation and friction and bear relevance to the shallow versus deep models debate in the context of the ongoing Juno mission. |
| P. Tamain, C. Colin, L. Colas, C. Baudoin, G. Ciraolo, R. Futtersack, D. Galassi, Ph Ghendrih, N. Nace, F. Schwander, E. Serre (2017): Numerical analysis of the impact of an RF sheath on the Scrape-Off Layer in 2D and 3D turbulence simulations. In: Nuclear Materials and Energy, pp. -, 2017, ISSN: 2352-1791. (Type: Journal Article | Abstract | Links | BibTeX) @article{Tamain2017, title = {Numerical analysis of the impact of an RF sheath on the Scrape-Off Layer in 2D and 3D turbulence simulations}, author = {P. Tamain and C. Colin and L. Colas and C. Baudoin and G. Ciraolo and R. Futtersack and D. Galassi and Ph Ghendrih and N. Nace and F. Schwander and E. Serre}, url = {http://www.sciencedirect.com/science/article/pii/S2352179116302757}, doi = {http://dx.doi.org/10.1016/j.nme.2016.12.022}, issn = {2352-1791}, year = {2017}, date = {2017-01-01}, journal = {Nuclear Materials and Energy}, pages = {-}, abstract = {Abstract Motivated by Radio Frequency (RF) heating studies, the response of the plasma of tokamaks to the presence of a locally polarized limiter is studied. In a first part, we use the TOKAM3X 3D global edge turbulence code to analyse the impact of such biasing in a realistic geometry. Key features of experimental observations are qualitatively recovered, especially the extension of a potential and density perturbation on long, but finite, distances along connected field lines. The perturbation is also found to extend in the transverse direction. Both observations demonstrate the influence of perpendicular current loops on the plasma confirming the need for an accurate description in reduced models. In a second part, we use the TOKAM2D slab turbulence code to determine the validity of using a transverse Ohm's law for this purpose. Results indicate that a local Ohm's law with a constant and uniform perpendicular resistivity appears at least as an oversimplified description of perpendicular charge transport in a turbulent Scrape-Off Layer.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Motivated by Radio Frequency (RF) heating studies, the response of the plasma of tokamaks to the presence of a locally polarized limiter is studied. In a first part, we use the TOKAM3X 3D global edge turbulence code to analyse the impact of such biasing in a realistic geometry. Key features of experimental observations are qualitatively recovered, especially the extension of a potential and density perturbation on long, but finite, distances along connected field lines. The perturbation is also found to extend in the transverse direction. Both observations demonstrate the influence of perpendicular current loops on the plasma confirming the need for an accurate description in reduced models. In a second part, we use the TOKAM2D slab turbulence code to determine the validity of using a transverse Ohm's law for this purpose. Results indicate that a local Ohm's law with a constant and uniform perpendicular resistivity appears at least as an oversimplified description of perpendicular charge transport in a turbulent Scrape-Off Layer. |
| H. Bufferand, C. Baudoin, J. Bucalossi, G. Ciraolo, J. Denis, N. Fedorczak, D. Galassi, Ph. Ghendrih, R. Leybros, Y. Marandet, N. Mellet, J. Morales, N. Nace, E. Serre, P. Tamain, M. Valentinuzzi (2017): Implementation of drift velocities and currents in SOLEDGE2D–EIRENE. In: Nuclear Materials and Energy, pp. -, 2017, ISSN: 2352-1791. (Type: Journal Article | Abstract | Links | BibTeX) @article{Bufferand2017, title = {Implementation of drift velocities and currents in SOLEDGE2D–EIRENE}, author = {H. Bufferand and C. Baudoin and J. Bucalossi and G. Ciraolo and J. Denis and N. Fedorczak and D. Galassi and Ph. Ghendrih and R. Leybros and Y. Marandet and N. Mellet and J. Morales and N. Nace and E. Serre and P. Tamain and M. Valentinuzzi}, url = {http://www.sciencedirect.com/science/article/pii/S2352179116301946}, doi = {http://dx.doi.org/10.1016/j.nme.2016.11.031}, issn = {2352-1791}, year = {2017}, date = {2017-01-01}, journal = {Nuclear Materials and Energy}, pages = {-}, abstract = {Abstract In order to improve cross-field transport description, drifts and currents have been implemented in SOLEDGE2D–EIRENE. The derivation of an equation for the electric potential is recalled. The resolution of current equation is tested in a simple slab case. WEST divertor simulations in forward-B and reverse-B fields are also discussed. A significant increase of ExB shear is observed in the forward-B configuration that could explain a favorable L-H transition in this case.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract In order to improve cross-field transport description, drifts and currents have been implemented in SOLEDGE2D–EIRENE. The derivation of an equation for the electric potential is recalled. The resolution of current equation is tested in a simple slab case. WEST divertor simulations in forward-B and reverse-B fields are also discussed. A significant increase of ExB shear is observed in the forward-B configuration that could explain a favorable L-H transition in this case. |
| G. Ciraolo, H. Bufferand, J. Bucalossi, Ph. Ghendrih, P. Tamain, Y. Marandet, M. Valentinuzzi, J. Denis, N. Fedorczak, E. Hodille, N. Mellet, B. Pegourie, C. Grisolia, C. Bourdelle, E. Tsitrone, D. Galassi, R. Leybros, G. Giorgiani, E. Serre (2017): H-mode WEST tungsten divertor operation: deuterium and nitrogen seeded simulations with SOLEDGE2D-EIRENE. In: Nuclear Materials and Energy, pp. -, 2017, ISSN: 2352-1791. (Type: Journal Article | Abstract | Links | BibTeX) @article{Ciraolo2017, title = {H-mode WEST tungsten divertor operation: deuterium and nitrogen seeded simulations with SOLEDGE2D-EIRENE}, author = {G. Ciraolo and H. Bufferand and J. Bucalossi and Ph. Ghendrih and P. Tamain and Y. Marandet and M. Valentinuzzi and J. Denis and N. Fedorczak and E. Hodille and N. Mellet and B. Pegourie and C. Grisolia and C. Bourdelle and E. Tsitrone and D. Galassi and R. Leybros and G. Giorgiani and E. Serre}, url = {http://www.sciencedirect.com/science/article/pii/S235217911630271X}, doi = {http://dx.doi.org/10.1016/j.nme.2016.12.025}, issn = {2352-1791}, year = {2017}, date = {2017-01-01}, journal = {Nuclear Materials and Energy}, pages = {-}, abstract = {Abstract Simulations of WEST H-mode divertor scenarios have been performed with SOLEDGE2D-EIRENE edge plasma transport code, both for pure deuterium and nitrogen seeded discharge. In the pure deuterium case, a target heat flux of 8 MW/m2 is reached, but misalignment between heat and the particle outflux yields 50 eV plasma temperature at the target plates. With nitrogen seeding, the heat and particle outflux are observed to be aligned so that lower plasma temperatures at the target plates are achieved together with the required high heat fluxes. This change in heat and particle outflux alignment is analysed with respect to the role of divertor geometry and the impact of vertical vs horizontal target plates on neutrals spreading.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Simulations of WEST H-mode divertor scenarios have been performed with SOLEDGE2D-EIRENE edge plasma transport code, both for pure deuterium and nitrogen seeded discharge. In the pure deuterium case, a target heat flux of 8 MW/m2 is reached, but misalignment between heat and the particle outflux yields 50 eV plasma temperature at the target plates. With nitrogen seeding, the heat and particle outflux are observed to be aligned so that lower plasma temperatures at the target plates are achieved together with the required high heat fluxes. This change in heat and particle outflux alignment is analysed with respect to the role of divertor geometry and the impact of vertical vs horizontal target plates on neutrals spreading. |
| Athanassoula, E., Rodionov, S. A., Prantzos, N. (2017): Metallicity-dependent kinematics and morphology of the Milky Way bulge. In: Monthly Notices of the Royal Astronomical Society: Letters, 467 (1), pp. L46, 2017. (Type: Journal Article | Links | BibTeX) @article{doi:10.1093/mnrasl/slw255, title = {Metallicity-dependent kinematics and morphology of the Milky Way bulge}, author = {Athanassoula, E. and Rodionov, S. A. and Prantzos, N.}, url = {+ http://dx.doi.org/10.1093/mnrasl/slw255}, doi = {10.1093/mnrasl/slw255}, year = {2017}, date = {2017-01-01}, journal = {Monthly Notices of the Royal Astronomical Society: Letters}, volume = {467}, number = {1}, pages = {L46}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| Gao, Xing, Bai, Shuming, Fazzi, Daniele, Niehaus, Thomas, Barbatti, Mario, Thiel, Walter (2017): Evaluation of Spin-Orbit Couplings with Linear-Response Time-Dependent Density Functional Methods. In: Journal of Chemical Theory and Computation, 13 (2), pp. 515-524, 2017, (PMID: 27959528). (Type: Journal Article | Abstract | Links | BibTeX) @article{doi:10.1021/acs.jctc.6b00915, title = {Evaluation of Spin-Orbit Couplings with Linear-Response Time-Dependent Density Functional Methods}, author = {Gao, Xing and Bai, Shuming and Fazzi, Daniele and Niehaus, Thomas and Barbatti, Mario and Thiel, Walter}, url = {http://dx.doi.org/10.1021/acs.jctc.6b00915}, doi = {10.1021/acs.jctc.6b00915}, year = {2017}, date = {2017-01-01}, journal = {Journal of Chemical Theory and Computation}, volume = {13}, number = {2}, pages = {515-524}, abstract = {A new versatile code based on Python scripts was developed to calculate spin–orbit coupling (SOC) elements between singlet and triplet states. The code, named PySOC, is interfaced to third-party quantum chemistry packages, such as Gaussian 09 and DFTB+. SOCs are evaluated using linear-response (LR) methods based on time-dependent density functional theory (TDDFT), the Tamm-Dancoff approximation (TDA), and time-dependent density functional tight binding (TD-DFTB). The evaluation employs Casida-type wave functions and the Breit-Pauli (BP) spin–orbit Hamiltonian with an effective charge approximation. For validation purposes, SOCs calculated with PySOC are benchmarked for several organic molecules, with SOC values spanning several orders of magnitude. The computed SOCs show little variation with the basis set, but are sensitive to the chosen density functional. The benchmark results are in good agreement with reference data obtained using higher-level spin–orbit Hamiltonians and electronic structure methods, such as CASPT2 and DFT/MRCI. PySOC can be easily interfaced to other third-party codes and other methods yielding CI-type wave functions.}, note = {PMID: 27959528}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new versatile code based on Python scripts was developed to calculate spin–orbit coupling (SOC) elements between singlet and triplet states. The code, named PySOC, is interfaced to third-party quantum chemistry packages, such as Gaussian 09 and DFTB+. SOCs are evaluated using linear-response (LR) methods based on time-dependent density functional theory (TDDFT), the Tamm-Dancoff approximation (TDA), and time-dependent density functional tight binding (TD-DFTB). The evaluation employs Casida-type wave functions and the Breit-Pauli (BP) spin–orbit Hamiltonian with an effective charge approximation. For validation purposes, SOCs calculated with PySOC are benchmarked for several organic molecules, with SOC values spanning several orders of magnitude. The computed SOCs show little variation with the basis set, but are sensitive to the chosen density functional. The benchmark results are in good agreement with reference data obtained using higher-level spin–orbit Hamiltonians and electronic structure methods, such as CASPT2 and DFT/MRCI. PySOC can be easily interfaced to other third-party codes and other methods yielding CI-type wave functions. |
| Dmytro Kandaskalov, Philippe Maugis (2017): A first-principle study of the structural, elastic, lattice dynamical and thermodynamic properties of and phases. In: Computational Materials Science, 128 , pp. 278 - 286, 2017, ISSN: 0927-0256. (Type: Journal Article | Abstract | Links | BibTeX) @article{Kandaskalov2017278, title = {A first-principle study of the structural, elastic, lattice dynamical and thermodynamic properties of and phases}, author = {Dmytro Kandaskalov and Philippe Maugis}, url = {http://www.sciencedirect.com/science/article/pii/S0927025616305730}, doi = {http://dx.doi.org/10.1016/j.commatsci.2016.11.022}, issn = {0927-0256}, year = {2017}, date = {2017-01-01}, journal = {Computational Materials Science}, volume = {128}, pages = {278 - 286}, abstract = {Abstract Low temperature decomposition of ferrous martensite leads to the formation of alternate C-rich and Fe-rich domains. Although some contradictions exist in the experimental results, the C-rich domains are often supposed to be the ordered α ″ - Fe 16 C 2 phase. The aim of our theoretical study is to investigate the fundamental properties of the α ″ - Fe 16 C 2 phase and to compare it to the isomorphic known phase α ″ - Fe 16 N 2 . In this paper, we present the structural, electronic, magnetic, vibrational and elastic properties of α ″ - Fe 16 C 2 and Fe 16 N 2 phases, calculated within the formalism of the DFT theory. This study is used to discuss the relative properties and stabilities of these two phases.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Low temperature decomposition of ferrous martensite leads to the formation of alternate C-rich and Fe-rich domains. Although some contradictions exist in the experimental results, the C-rich domains are often supposed to be the ordered α ″ - Fe 16 C 2 phase. The aim of our theoretical study is to investigate the fundamental properties of the α ″ - Fe 16 C 2 phase and to compare it to the isomorphic known phase α ″ - Fe 16 N 2 . In this paper, we present the structural, electronic, magnetic, vibrational and elastic properties of α ″ - Fe 16 C 2 and Fe 16 N 2 phases, calculated within the formalism of the DFT theory. This study is used to discuss the relative properties and stabilities of these two phases. |
