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Jolliet, S.; McMillan, B. F.*; Villard, L.*; Vernay, T.*; Angelino, P.*; Tran, T. M.*; Brunner, S.*; Bottino, A.*; Idomura, Yasuhiro
Journal of Computational Physics, 231(3), p.745 - 758, 2012/02
Times Cited Count:14 Percentile:61.76(Computer Science, Interdisciplinary Applications)Labit, B.*; Pochelon, A.*; Rancic, M.*; Piras, F.*; Bencze, A.*; Bottino, A.*; Brunner, S.*; Camenen, Y.*; Chattopadhyay, P. K.*; Coda, S.*; et al.
Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03
Villard, L.*; Bottino, A.*; Brunner, S.*; Casati, A.*; Chowdhury, J.*; Dannert, T.*; Ganesh, R.*; Garbet, X.*; Grler, T.*; Grandgirard, V.*; et al.
Plasma Physics and Controlled Fusion, 52(12), p.124038_1 - 124038_18, 2010/11
Times Cited Count:21 Percentile:60.74(Physics, Fluids & Plasmas)McMillan, B. F.*; Lapillonne, X.*; Brunner, S.*; Villard, L.*; Jolliet, S.; Bottino, A.*; Grler, T.*; Jenko, F.*
Physical Review Letters, 105(15), p.155001_1 - 155001_4, 2010/10
Times Cited Count:108 Percentile:93.64(Physics, Multidisciplinary)Bottino, A.*; Scott, B. D.*; Brunner, S.*; McMillan, B. F.*; Tran, T. M.*; Vernay, T.*; Villard, L.*; Jolliet, S.; Hatzky, R.*; Peeters, A. G.*
IEEE Transactions on Plasma Science, 38(9), p.2129 - 2135, 2010/09
Times Cited Count:26 Percentile:67.96(Physics, Fluids & Plasmas)Garbet, X.*; Idomura, Yasuhiro; Villard, L.*; Watanabe, Tomohiko*
Nuclear Fusion, 50(4), p.043002_1 - 043002_30, 2010/04
Times Cited Count:285 Percentile:74.19(Physics, Fluids & Plasmas)This overview is an assessment of the gyrokinetic framework and simulations to compute the turbulent transport in fusion plasmas. It covers an introduction to the gyrokinetic theory, the principal numerical techniques which are being used to solve the gyrokinetic equations, fundamentals in gyrokinetic turbulence and the main results which have been brought by simulations with regard to transport in fusion devices and actuation measurements.
Jolliet, S.*; Bottino, A.*; Angelino, P.*; Hatzky, R.*; Tran, T. M.*; McMillan, B. F.*; Sauter, O.*; Appert, K.*; Idomura, Yasuhiro; Villard, L.*
Computer Physics Communications, 177(5), p.409 - 425, 2007/09
Times Cited Count:192 Percentile:98.52(Computer Science, Interdisciplinary Applications)A global plasma turbulence simulation code, ORB5, is presented. A particular feature is the use of straight-field-line magnetic coordinates and a field-aligned Fourier filtering technique that dramatically improves the performance of the code in terms of both the numerical noise reduction and the maximum time step allowed. Another feature is the capability to treat arbitrary axisymmetric ideal MHD equilibrium configurations. The code is validated against an analytical theory of zonal flows and against other codes for a selection of linear and nonlinear tests.
Idomura, Yasuhiro; Ida, Masato; Tokuda, Shinji; Villard, L.*
Journal of Computational Physics, 226(1), p.244 - 262, 2007/09
Times Cited Count:32 Percentile:78.06(Computer Science, Interdisciplinary Applications)A new conservative gyrokinetic full- Vlasov code is developed using a finite difference operator which conserves both the
and
norms. The growth of numerical oscillations is suppressed by conserving the
norm, and the code is numerically stable and robust in a long time simulation. In the slab ion temperature gradient driven (ITG) turbulence simulation, the energy conservation and the entropy balance relation are confirmed, and solutions are benchmarked against a conventional
particle-in-cell (PIC) code. The results show that the exact particle number conservation and the good energy conservation in the conservative Vlasov simulation are advantageous for a long time micro-turbulence simulation. In the comparison, physical and numerical effects of the
nonlinearity are clarified for the Vlasov and PIC simulations.
Idomura, Yasuhiro; Ida, Masato; Tokuda, Shinji; Villard, L.*
Europhysics Conference Abstracts (CD-ROM), 30I, 4 Pages, 2006/00
A gyrokinetic simulation is an essential tool to study turbulent anomalous transport in tokamak plasmas, and a long time global simulation of driven turbulence in open system is highly desirable towards estimation and prediction of turbulent transport. However, poor conservation properties in conventional gyrokinetic simulations were problematic in such a long time simulation. To overcome this difficulty, a new conservative gyrokinetic code is developed using Morinishi scheme, which was originally developed for conservative simulations of neutral fluid turbulence. In the new code, in addition to the exact particle number conservation, the energy conservation is dramatically improved, and the scheme is robust in a long time simulation. In slab ion temperature gradient driven turbulence simulations, comparisons of the new code and a conventional particle code are presented.
Villard, L.*; Angelino, P.*; Bottino, A.*; Allfrey, S. J.*; Hatzky, R.*; Idomura, Yasuhiro; Sauter, O.*; Tran, T. M.*
Plasma Physics and Controlled Fusion, 46(12B), p.B51 - B62, 2004/12
Times Cited Count:29 Percentile:66.24(Physics, Fluids & Plasmas)This paper reviews the present status of recent first principles based plasma turbulence simulations, and gives quantitative discussions on influences of the v// nonlinearlity and the geometry effects in the gyrokinetic Poisson equaiton, which are ignored in the conventional approximations, on simulations results. Careful treatments of these effects enable turbulence simulations satisfying the conservation of the energy and the particle number. The new simulation disclosed new phenomena, and it is found that (1) turbulence spreading is induced by avalanche like phnemena consisting of bursty heat transport and local flattening of pressure profiles, and (2) nonlinearly driven EB flows become global shear flows with scale lengths of about 30 ion gyro radii.
Bottino, A.*; Angelino, P.*; Allfrey, S. J.*; Brunner, S.*; Hatzky, R.*; Idomura, Yasuhiro; Jolliet, S.*; Sauter, O.*; Tran, T. M.*; Villard, L.*
Theory of Fusion Plasmas, ISPP21, p.75 - 86, 2004/00
The global nonlinear electrostatic PIC code ORB5 solves the gyrokinetic Vlasov-Poisson system assuming adiabatic electrons in realistic tokamak magnetohydrodynamic (MHD) equilibria. The present version of ORB5 shows remarkable particle and energy conservation properties and can be used for physics studies in toroidal geometry. In particular, the optimized tracer loading method has been adapted to tokamak geometry and implemented in ORB5 together with a new adaptive gyro-average algorithm. Basic physical conservation properties (energy and particle number) are used as indicators of the quality of the numerical simulations. In this paper we present the first nonlinear results of electrostatic collisionless microinstabilities of realistic MHD shaped equilibria, provided by the MHD equilibrium code CHEASE, including the toroidicity induced geometrical coupling of the zonal ExB flow and the parallel velocity nonlinearlity.
Jolliet, S.*; Angelino, P.*; Bottino, A.*; Idomura, Yasuhiro; Villard, L.*
Theory of Fusion Plasmas, ISPP21, p.345 - 351, 2004/00
Global particle-in-cell (PIC) simulations are a very useful tool for studying the time evolution of turbulence induced by ion-temperature-gradient (ITG) instabilities. Unfortunately, the linear code LORB5 and its non-linear version ORB5 require high computational power. In order to study more sophisticated models, we need to optimize these codes. We will focus on LORB5, which uses a cylindrical grid (r,z) for solving the Vlasov equation and a (s,) grid for the Poisson equation. The approach presented in this work consists of implementing the gyrokinetic model using a single (s,
) grid. Here
is the straight-field-line poloidal coordinate. A method to avoid the singularity at the magnetic axis is presented, and a benchmark with the CYCLONE case is shown.
Idomura, Yasuhiro; Ida, Masato; Tokuda, Shinji; Villard, L.*
no journal, ,
no abstracts in English
Jolliet, S.; McMillan, B. F.*; Bottino, A.*; Angelino, P.*; Lapillonne, X.*; Vernay, T.*; Idomura, Yasuhiro; Villard, L.*
no journal, ,
Vernay, T.*; Brunner, S.*; Villard, L.*; Jolliet, S.; McMillan, B. F.*; Lapillonne, X.*
no journal, ,
McMillan, B. F.*; Jolliet, S.; Tran, T. M.*; Bottino, A.*; Lapillonne, X.*; Villard, L.*
no journal, ,
Idomura, Yasuhiro; Matsuoka, Seikichi; Ina, Takuya; Garbet, X.*; Brunner, S.*; Villard, L.*; Kawai, Chika*
no journal, ,
This talk reviews outcomes from GT5DISO projects, which was conducted for FY2014-2016. In this project, isotope effects on turbulent transport have been studied using the gyrokinetic toroidal five dimensional full-f Eulerian code GT5D. In FY2014, it was shown that the ion temperature gradient driven (ITG) turbulence with adiabatic electrons does not show isotope effects, and the trapped electron mode (TEM) driven by kinetic trapped electrons is essential for this issue. In FY2015, a new hybrid kinetic electron model was developed in GT5D, and its verification tests for ITG-TEM turbulence simulations were conducted. In FY2016, the kinetic electron model was validated against electron heating modulation experiments, in which the TEM turbulence plays key roles in particle and momentum transport. Finally, we performed isotope scan of ITG-TEM turbulence simulations, which tend to indicate difference of confinement between hydrogen and deuterium plasmas.
Kikuchi, Mitsuru; Fasoli, A.*; Takizuka, Tomonori*; Diamond, P.*; Medvedev, S.*; Duan, X.*; Zushi, Hideki*; Furukawa, Masaru*; Kishimoto, Yasuaki*; Wu, Y.*; et al.
no journal, ,
Power and particle control is challenging for standard D-shaped H-mode scenario in tokamak. Possibility of negative triangularity as innovative tokamak concept is discussed by Kikuchi et al. Experimental and numerical studies of negative triangular plasma at CRPP-EPFL success-fully demonstrated improved connement and the weakening of the SOL flow acceleration is implied for the negative triangularity. Recent studies on mechanism of type II and grassy ELM show importance of closure of second stability access to achieve small ELM regimes and also kinetic effects. Medvedev showed that closure of second stability also occurs for negative triangularity. But the MHD stability in negative triangularity is a bit more complicated so that closure of second stability does not imply easy access to small ELM regimes. We discuss critical elements behind.
Jolliet, S.*; Villard, L.*; Idomura, Yasuhiro; McMillan, B. F.*; Bottino, A.*; Lapillonne, X.*
no journal, ,
no abstracts in English