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 gyrokinetic study of density gradient driven instability in tokamaks: the ubiquitous mode
 
research article

Global gyrokinetic study of density gradient driven instability in tokamaks: the ubiquitous mode

Choudhary, Sagar
•
Chowdhury, Jugal
•
Gopal Krishna, M.
Show more
August 1, 2024
Plasma Physics and Controlled Fusion

The ubiquitous mode is investigated in the linear regime for the first time using a global gyrokinetic model. These modes are driven by the density gradient in trapped electron population but with mode frequency in the ion diamagnetic drift direction, in contrast to the conventional trapped electron mode. The dispersion relation is calculated along with the global mode structure. The ubiquitous mode is quite global although appears at a shorter wavelength ( 1 2 k y 2 ρ i 2 > 1 ). We show that the main driving mechanism is the density gradient and the temperature gradient has only a modest effect; the mode can persist at higher temperature gradient scenarios making it another possible channel of anomalous transport. The magnetic shear reduces the growth of the mode; while the electron to ion temperature ratio has a nonmonotonic effect on the mode growth rate—growth rate increases initially for the ubiquitous branch of the mode and decreases afterwards as the conventional trapped electron mode starts dominating. The role of safety factor and toroidicity is also analyzed. Finally, a mixing length-based estimation of transport is presented.

  • Details
  • Metrics
Type
research article
DOI
10.1088/1361-6587/ad5bfe
Scopus ID

2-s2.0-85198023323

Author(s)
Choudhary, Sagar

Institute for Plasma Research

Chowdhury, Jugal

Institute for Plasma Research

Gopal Krishna, M.

Institute for Plasma Research

Mahapatra, Jagannath

Institute for Plasma Research

Singh, Amit K.

Institute for Plasma Research

Ganesh, Rajaraman

Institute for Plasma Research

Villard, Laurent  

École Polytechnique Fédérale de Lausanne

Date Issued

2024-08-01

Published in
Plasma Physics and Controlled Fusion
Volume

66

Issue

8

Article Number

085013

Subjects

gyrokinetic

•

microinstabilities

•

Orb5

•

TEM

•

tokamak

•

ubiquitous mode

•

universal mode

Editorial or Peer reviewed

REVIEWED

Written at

EPFL

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

HBNI

Available on Infoscience
January 23, 2025
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/243245
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