Whole-volume integrated gyrokinetic simulation of plasma turbulence in realistic diverted-tokamak geometry

Chang, C. S.; Ku, S.; Diamond, P. H.; Adams, Mark F.; Barreto, R.; Chen, Y; Cummings, Julian; D’Azevedo, E.; Dif‐Pradalier, G.; Ethier, S.; Greengard, Leslie; Hahm, T. S.; Hinton, F. L.; Keyes, David E.; Klasky, Scott; Zhang, Lin; Lofstead, Jay; Park, G; Parker, Scott; Podhorszki, Norbert; Schwan, Karsten; Shoshani, Arie; Silver, Deborah; Wolf, Matthew; Worley, Patrick H; Weitzner, Harold; Yoon, Eisung; Zorin, Denis

doi:10.1088/1742-6596/180/1/012057

Cited by 24 publications

(18 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By ordering the gyro-motion as the fastest time scale, the three-dimensional velocity space can be reduced to a two-dimensional domain. Global gyrokinetic turbulent simulations have been extended to cover the SOL domain and take into account also neutral physics (Chang et al 2009) as well as spatially onedimensional simulations of the tokamak SOL have been performed (Shi et al 2014). While some advances in the study of the edge dynamics have been obtained through the use of the kinetic simulations, because of their numerical cost, fluid codes still remain the model of reference to perform the large parameter scans of SOL turbulence simulations needed to deepen our understanding of SOL physics.…”

Section: Kinetic Description Of the Sol Dynamicsmentioning

confidence: 99%

Simulation of the scrape-off layer region of tokamak devices

Ricci

2015

J. Plasma Phys.

View full text Add to dashboard Cite

Understanding the key processes occurring in the tokamak scrape-off layer (SOL) is becoming of the outmost importance while we enter the ITER era and we move towards the conception of future fusion reactors. By controlling the heat exhaust, by playing an important role in determining the overall plasma confinement, and by regulating the impurity level in tokamak core, the dynamics of the fusion fuel in the SOL is, in fact, related to some of the most crucial issues that the fusion program is facing today. Because of the limited diagnostic access and in view of predicting the SOL dynamics in future devices, simulations are becoming crucial to address the physics of this region. The present paper, which summarizes the lecture on SOL simulations that was given during the 7th ITER international school (August 25-29, 2014, Aix-en-Provence, France), provides a brief overview of the simulation approaches to the SOL dynamics. First, disentangling the complexity of the system, the key physics processes occurring in the SOL are described. Then, the different simulation approaches to the SOL dynamics are presented, from first-principles kinetic and fluid models, to the phenomenological analysis.

show abstract

Section: Kinetic Description Of the Sol Dynamicsmentioning

confidence: 99%

Simulation of the scrape-off layer region of tokamak devices

Ricci

2015

J. Plasma Phys.

View full text Add to dashboard Cite

show abstract

“…Therefore, they have an extremely high numerical cost and could so far be applied only to one-dimensional geometries 85 . Recently, the 3D simulation of SOL dynamics has been approached by extending global gyrokinetic models to cover the SOL domain 86,87 and by also taking into account the e ect of neutral particles using fluid codes. Starting from a set of fluid equations for collisional plasmas developed by Braginskii in 1965 88 , or by integrating the gyrokinetic equations in velocity space, a number of models more suited for computational treatment were deduced 89,90 and are now implemented in a number of codes [91][92][93] .…”

Section: Edge Transport and Plasma-wall Interactionsmentioning

confidence: 99%

Computational challenges in magnetic-confinement fusion physics

et al. 2016

View full text Add to dashboard Cite

Magnetic-fusion plasmas are complex self-organized systems with an extremely wide range of spatial and temporal scales, from the electron-orbit scales (⇠10 11 s, ⇠10 5 m) to the di usion time of electrical current through the plasma (⇠10 2 s) and the distance along the magnetic field between two solid surfaces in the region that determines the plasma-wall interactions (⇠100 m). The description of the individual phenomena and of the nonlinear coupling between them involves a hierarchy of models, which, when applied to realistic configurations, require the most advanced numerical techniques and algorithms and the use of state-of-the-art high-performance computers. The common thread of such models resides in the fact that the plasma components are at the same time sources of electromagnetic fields, via the charge and current densities that they generate, and subject to the action of electromagnetic fields. This leads to a wide variety of plasma modes of oscillations that resonate with the particle or fluid motion and makes the plasma dynamics much richer than that of conventional, neutral fluids.T he most straightforward way for describing plasmas would be the microscopic particle approach: solving the equations of motion for the many individual particles that form the plasma in externally imposed electromagnetic fields and in the fields that the particles themselves generate. However, this is computationally impossible to apply to realistic magnetic-fusion plasmas, which typically contain 10 22 -10 23 particles. (For a review of the basic concepts of magnetically confined fusion plasmas, see ref. 1.)A statistical treatment leads to the kinetic model, based on the Vlasov equation (equation (1)), essentially Liouville's theorem applied to the specific plasma environment, with interactions that are dominated by electromagnetic fields and a separation between particle collisions -that is, interactions at microscopic scales-and long-range fields. The Vlasov equation describes the evolution of f s (x,v,t), the single-particle phase-space distribution function of the species labelled 's' (electrons or ions), under the e ect of the longrange electric and magnetic fields E and B, which evolve according to Maxwell's equations with plasma charge and current densities as sources:Here, x, v, q s and m s stand for the position, velocity, charge and the mass of a particle of species 's' , respectively. In the Vlasov model, collisions are neglected, an approximation that is generally justified for fusion plasmas because small-scale e ects based on Coulomb interactions become very weak at high temperatures. In fact, Coulomb collisions' cross-sections for the exchange of momentum and energy, and related quantities such as the electrical resistivity ⌘, scale with T 3/2 . In ITER core plasmas (see ref. 1), for example, T ⇡ 10 keV (⇡10 8 K) and the electron-electron ('ee'), electron-ion ('ei') and ion-ion ('ii') collisional exchanges of momentum and energy ('E') occur over relatively long characteristic times:2)-justifying the collisi...

show abstract

“…48,49 XGC1s simulation domain uniquely extends from the material wall boundary to the magnetic axis across the magnetic separatrix, with the neutral particle recycling at the wall, and it covers a broad range of relevant physics, including the H-mode physics. XGC1 uses the fully nonlinear Fokker-Planck collision operator for modeling of the non-thermal equilibrium plasma physics in the edge region of a magnetic fusion reactor.…”

Section: Iiic Applied Research: Fusionmentioning

confidence: 99%

Outcomes from the DOE Workshop on Turbulent Flow Simulation at the Exascale

Sprague

Boldyrev

Chang

et al. 2016

46th AIAA Fluid Dynamics Conference

View full text Add to dashboard Cite

ing Research (ASCR). The workshop objectives were to define and describe the challenges and opportunities that computing at the exascale will bring to turbulent-flow simulations in applied science and technology. The need for accurate simulation of turbulent flows is evident across the DOE applied-science and engineering portfolios, including combustion, plasma physics, nuclear-reactor physics, wind energy, and atmospheric science. The workshop brought together experts in turbulent-flow simulation, computational mathematics, and high-performance computing. Building upon previous ASCR workshops on exascale computing, participants defined a research agenda and path forward that will enable scientists and engineers to continually leverage, engage, and direct advances in computational systems on the path to exascale computing.

show abstract

Whole-volume integrated gyrokinetic simulation of plasma turbulence in realistic diverted-tokamak geometry

Cited by 24 publications

References 18 publications

Simulation of the scrape-off layer region of tokamak devices

Simulation of the scrape-off layer region of tokamak devices

Computational challenges in magnetic-confinement fusion physics

Outcomes from the DOE Workshop on Turbulent Flow Simulation at the Exascale

Contact Info

Product

Resources

About