Repository logo

Infoscience

  • English
  • French
Log In
Logo EPFL, École polytechnique fédérale de Lausanne

Infoscience

  • English
  • French
Log In
  1. Home
  2. Academic and Research Output
  3. Journal articles
  4. Global electromagnetic gyrokinetic simulations of internal transport barriers in reversed-shear tokamaks
 
research article

Global electromagnetic gyrokinetic simulations of internal transport barriers in reversed-shear tokamaks

Di Giannatale, Giovanni  
•
Volčokas, Arnas  
•
Ball, Justin  
Show more
July 31, 2025
Plasma Physics and Controlled Fusion

Internal transport barriers (ITB) form through turbulence suppression, often observed when the safety factor profile exhibits an off-axis minimum. This work aims at improving our understanding of the conditions enabling the development of an ITB, using a more comprehensive physical model, including low-β electromagnetic flux-driven simulations. Our key findings are that electron dynamics is crucial for ITB formation even in an ITG scenario and that having qmin close to a lowest order rational value (2 in our simulations) to allow for eddies self-interaction is a necessary ingredient. Electron dynamics has two critical effects. First, it leads to a structure formation characterized by strong zonal flows shearing rate, quench of turbulence (i.e. reduction of transport coefficients and fluctuation correlation) and profile corrugation. Second, it leads to zonal current sheets that result in a broadening of the minimum-q region, qualitatively consistent with the flux-tube simulations of Volčokas et al (2024 arXiv:2412.01913). Flux-driven simulations performed with q min = 2 reveal the development of the transport barrier in the ion channel, forming at inner and outer radial positions with respect to the qmin position. The ITB formation in flux-driven setup is not recovered if q min = 2.03 . Additionally, a simulation at higher ρ ∗ indicates that the extent of the flattened region of the q-profile due to turbulent self-interaction does not change proportionally to ρ ∗ or to ρi, but somewhere in between. On the other hand, the input power required to achieve similar on-axis temperatures appears to exhibit almost gyro-Bohm scaling (for the two considered ρ ∗ values). Furthermore, considering an initial q-profile with q min = 2.01 , flux-driven simulations show that partial self-interaction can evolve to complete self-interaction. This occurs due to turbulent-driven zonal currents that lower and flatten the q-profile down to q min = 2.0 , in line with what is reported in Volčokas et al (2024 arXiv:2412.01913).

  • Files
  • Details
  • Metrics
Type
research article
DOI
10.1088/1361-6587/ade1f7
Scopus ID

2-s2.0-105009037451

Author(s)
Di Giannatale, Giovanni  

École Polytechnique Fédérale de Lausanne

Volčokas, Arnas  

École Polytechnique Fédérale de Lausanne

Ball, Justin  

École Polytechnique Fédérale de Lausanne

Bottino, Alberto

Max Planck Institute for Plasma Physics

Brunner, Stephan  

École Polytechnique Fédérale de Lausanne

Griveaux, Philippe  

École Polytechnique Fédérale de Lausanne

Murugappan, Moahan  

École Polytechnique Fédérale de Lausanne

Hayward-Schneider, Thomas

Max Planck Institute for Plasma Physics

Villard, Laurent  

École Polytechnique Fédérale de Lausanne

Date Issued

2025-07-31

Published in
Plasma Physics and Controlled Fusion
Volume

67

Issue

7

Article Number

075008

Subjects

gyrokinetic

•

ITB

•

turbulence

Editorial or Peer reviewed

REVIEWED

Written at

EPFL

EPFL units
SPC-TH  
FunderFunding(s)Grant NumberGrant URL

SERI

Swiss State Secretariat for Education, Research and Innovation

Swiss National Science Foundation

Show more
Available on Infoscience
July 4, 2025
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/251898
Logo EPFL, École polytechnique fédérale de Lausanne
  • Contact
  • infoscience@epfl.ch

  • Follow us on Facebook
  • Follow us on Instagram
  • Follow us on LinkedIn
  • Follow us on X
  • Follow us on Youtube
AccessibilityLegal noticePrivacy policyCookie settingsEnd User AgreementGet helpFeedback

Infoscience is a service managed and provided by the Library and IT Services of EPFL. © EPFL, tous droits réservés