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. Numerical characterization of bump formation in the runaway electron tail
 
research article

Numerical characterization of bump formation in the runaway electron tail

Decker, J
•
Hirvijoki, E
•
Embreus, O
Show more
2016
Plasma Physics and Controlled Fusion

Runaway electrons are generated in a magnetized plasma when the parallel electric field exceeds a critical value. For such electrons with energies typically reaching tens of MeV, the Abrahamâ Lorentzâ Dirac (ALD) radiation force, in reaction to the synchrotron emission, is significant and can be the dominant process limiting electron acceleration. The effect of the ALD force on runaway electron dynamics in a homogeneous plasma is investigated using the relativistic finite-difference Fokkerâ Planck codes LUKE (Decker and Peysson 2004 Report EUR-CEA-FC-1736, Euratom-CEA), and CODE (Landreman et al 2014 Comput. Phys. Commun. 185 847). The time evolution of the distribution function is analyzed as a function of the relevant parameters: parallel electric field, background magnetic field, and effective charge. Under the action of the ALD force, we find that runaway electrons are subject to an energy limit, and that the electron distribution evolves towards a steady-state. In addition, a bump is formed in the tail of the electron distribution function if the electric field is sufficiently strong. The mechanisms leading to the bump formation and energy limit involve both the parallel and perpendicular momentum dynamics; they are described in detail. An estimate for the bump location in momentum space is derived. We observe that the energy of runaway electrons in the bump increases with the electric field amplitude, while the population increases with the bulk electron temperature. The presence of the bump divides the electron distribution into a runaway beam and a bulk population. This mechanism may give rise to beam-plasma types of instabilities that could, in turn, pump energy from runaway electrons and alter their confinement.

  • Details
  • Metrics
Type
research article
DOI
10.1088/0741-3335/58/2/025016
Web of Science ID

WOS:000371570900017

Author(s)
Decker, J
Hirvijoki, E
Embreus, O
Peysson, Y
Stahl, A
Pusztai, I
Fulop, T
Date Issued

2016

Publisher

Iop Publishing Ltd

Published in
Plasma Physics and Controlled Fusion
Volume

58

Article Number

025016

Subjects

runaway electron

•

Abraham-Lorentz-Dirac

•

synchrotron emission

•

kinetic instabilities

•

Fokker-Planck

URL

URL

https://crpplocal.epfl.ch/pinboard/jpapers/1501005.pdf
Editorial or Peer reviewed

REVIEWED

Written at

EPFL

EPFL units
SPC  
Available on Infoscience
January 26, 2016
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/122710
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