Simulation of the scrape-off layer region of tokamak devices

Ricci, Paolo

doi:10.1017/s0022377814001202

Cited by 16 publications

(18 citation statements)

References 51 publications

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“…In the past decade, several computational models were developed and implemented into numerical codes, that are used to investigate the tokamak SOL dynamics [7][8][9][10][11][12][13][14][15][16]. The main instabilities driving the SOL turbulence were characterized in the simplest SOL configuration (i.e.…”

Section: Introductionmentioning

confidence: 99%

Plasma shaping effects on tokamak scrape-off layer turbulence

Riva

Lanti

Jolliet

et al. 2017

Plasma Phys. Control. Fusion

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The impact of plasma shaping on tokamak scrape-off layer (SOL) turbulence is investigated. The drift-reduced Braginskii equations are written for arbitrary magnetic geometries, and an analytical equilibrium model is used to introduce the dependence of turbulence equations on tokamak inverse aspect ratio ( ), Shafranov's shift (∆), elongation (κ), and triangularity (δ). A linear study of plasma shaping effects on the growth rate of resistive ballooning modes (RBMs) and resistive drift waves (RDWs) reveals that RBMs are strongly stabilized by elongation and negative triangularity,

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Section: Introductionmentioning

confidence: 99%

Plasma shaping effects on tokamak scrape-off layer turbulence

Riva

Lanti

Jolliet

et al. 2017

Plasma Phys. Control. Fusion

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“…Moreover, SOL dynamics determines the heat load to the walls, a potential showstopper for fusion if material limits (⇠10 MW m 2 ) are exceeded 77,78 . Simulating SOL plasma dynamics is particularly challenging 79 . First, transport in the SOL is highly intermittent and, unlike in the tokamak core, is dominated by large fluctuations, the amplitudes of which are comparable to the equilibrium quantities.…”

Section: Edge Transport and Plasma-wall Interactionsmentioning

confidence: 99%

Computational challenges in magnetic-confinement fusion physics

et al. 2016

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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...

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“…However, collisions are a key driver to transport particles across closed magnetic flux surfaces that would be confined otherwise. [6] . They cause plasma to diffuse from the confined region into the SOL and from there they are transported towards the device wall.…”

Section: Introductionmentioning

confidence: 99%

“…They cause plasma to diffuse from the confined region into the SOL and from there they are transported towards the device wall. [6] Due to lower temperature, collisionality is also higher in the SOL than in the core region. Therefore, in this study we implement a Lenard-Bernstein (LB) collision operator in our newly developed PICLS code, which is designed to perform gyrokinetic SOL simulations.…”

Section: Introductionmentioning

confidence: 99%

Collisional gyrokinetic full‐f particle‐in‐cell simulations on open field lines with PICLS

Boesl

Bergmann

Bottino

et al. 2019

Contributions to Plasma Physics

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Applying gyrokinetic simulations for theoretical turbulence and transport studies to the plasma edge and scrape-off layer (SOL) presents significant challenges. To in particular account for steep density and temperature gradients in the SOL, the "full-f" code PICLS was developed. PICLS is a gyrokinetic particle-in-cell (PIC) code and is based on an electrostatic model with a linearized field equation and uses kinetic electrons. In previously published results we were applying PICLS to the well-studied 1D parallel transport problem during an edge-localized mode (ELM) in the SOL without collisions. As an extension to this collision-less case and in preparation for 3D simulations, in this work a collisional model will be introduced. The implemented Lenard-Bernstein collision operator and its Langevin discretization will be shown.Conservation properties of the collision operator as well as a comparison of the collisional and non-collisional case will be discussed.

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Simulation of the scrape-off layer region of tokamak devices

Cited by 16 publications

References 51 publications

Plasma shaping effects on tokamak scrape-off layer turbulence

Plasma shaping effects on tokamak scrape-off layer turbulence

Computational challenges in magnetic-confinement fusion physics

Collisional gyrokinetic full‐f particle‐in‐cell simulations on open field lines with PICLS

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