Simulations of the core sol transition of a tokamak plasma
Sponsored Links
This presentation is the property of its rightful owner.
1 / 18

Simulations of the core/SOL transition of a tokamak plasma PowerPoint PPT Presentation

  • Uploaded on
  • Presentation posted in: General

Simulations of the core/SOL transition of a tokamak plasma. Frederic Schwander ,Ph. Ghendrih, Y. Sarazin IRFM/CEA Cadarache G. Ciraolo, E. Serre, L. Isoardi, G. Chiavassa M2P2, Marseille. Technological impacts of the study of edge turbulence.

Download Presentation

Simulations of the core/SOL transition of a tokamak plasma

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Simulations of the core/SOL transition of a tokamak plasma

Frederic Schwander,Ph. Ghendrih, Y. Sarazin IRFM/CEA Cadarache

G. Ciraolo, E. Serre, L. Isoardi, G. Chiavassa

M2P2, Marseille

Technological impacts of the study of edge turbulence

  • Determination of profiles: density, temperatureOptimization of plasma performance

  • Determinationheat fluxes on plasma-facing componentsEstablishment of constraints on plasma operationswithappropriate thermal load on plasma facing components

« Academic » impacts of the study of edge turbulence

  • Core-SOL transition intrinsicallysheared

  • Active role on turbulence ?

  • Propagation of turbulence betweencore and SOL ?

  • Impact of three-dimensionaleffects on edge turbulence.

The limiter: at the center of the study




  • Core plasma

  • Closed magnetic surfaces in the core

  • Double periodicity:

  • poloidal angle

  • toroidal angle

  • Scrape-off layer

  • Field lines intersect both sides of limiter

  • Poloidal periodicity lost,

  • Only toroidal periodicity preserved.

Field lines intersect limiter on inboard and outboard side

Core/SOL transition: an intrisicallyshearedregion


  • Parallelflowsessentiallyatrest

  • Relatively large density

    Scrape-off layer

  • High velocityparallelflows

  • Lowdensity

    Shear in momentum and densityat the transition:

    Triggering of instabilities ?



Kelvin-Helmholtz instability

  • Driven by shear in parallel momentum

  • Stabilized by density gradient

  • Instability criterion (WKB analysis)

Model equations

Particle conservation (n paticle density)

Momentum conservation (Γ parallel momentum)

Additional equation – electric drift

Model equations – elementarymechanisms

Particle conservation

Momentum conservation

Acoustic waves: finite parallel wavenumber

Drift waves : finite perpendicular wavenumber

Dynamics only accessible through 3D simulations


  • Cylindricaldomain(no curvatureatthis stage)

  • Non-periodiccoordinates(radial, poloidal)

    • Second-orderfinitedifferences

  • Periodic direction (toroidal)

    • Fourier modes

  • Paralleldynamics: Lax-Wendroff TVD scheme

  • Advection by drift motion: Arakawa scheme

  • Background turbulent transport:treatedimplicitly

Axisymmetric equilibria

Systematic convergence of axisymmetric computation towards steady state.


Natural radial stratification in density,

Large Mach number flows limited to scrape-off layer.

Large gradients at the transition





  • Maximum gradient increases when background turbulence decreases.

  • Kelvin-Helmholtz instability: stabilizing and destabilizing factors maximum at the same location. Overall effect ?

Radial profiles of the instabilityparameter

  • Stabilization by density stratification globally dominant,

  • Global stability for lowest values of transport

  • Unstable region just inside the transition for largest value of transport.



Linear instability growth

Simulation parameters



Resolution 100x64x32

Linear instability of mode with toroidal wavenumber n=1.

Most unstable mode (n=1)

Localized on corner of limiter

Toroidal mode n=3

  • Mode driven close to the limiter

  • Larger poloidal extent than n=1


  • Possible excitation of Kelvin-Helmholtz modes in reduced model of core/SOL dynamics,

  • Instability favoured for large values of background turbulence,

  • Mode not driven at core/SOL transition, but on top of limiter.


  • Systematic study of linear growth of non-axisymmetric perturbations

  • Nonlinear phase

  • Extension of model to take into account interchange instability.

  • Login