Skip to content
DraconiticResearch
Search Sources API
194,161 studies31 sourcesUpdated 23 min ago
Peer-reviewedCC BY 4.0The Astrophysical Journal

Collisionless Electron Heat Flux for the Nonequilibrium Solar Wind Plasma: Revisiting Hollweg’s Parameter

  • Klaus Scherer1
  • Lukas Westrich1,2
  • Marian Lazar1,3
  • Horst Fichtner1
  • Stefaan Poedts3,4
4 affiliations
  1. 1Ruhr-Universität Bochum
  2. 2Ilia State University
  3. 3KU Leuven
  4. 4University of Maria Curie-Skłodowska
Open at sourcePDFDOICite

Abstract

Here, we discuss an extension of the modelling of the collisionless heat flux and the related parameter α , derived by Hollweg for a truncated Maxwellian to distributions with suprathermal tails. In the collisionless solar wind plasma, electrons and ions are described by a multitude of non-Maxwellian (nonequilibrium) velocity distributions, such as the standard, regularized κ , and Druyvesteyn distributions. We show that for these nonidealized distributions, the heat flux and the related parameter α can deviate significantly from the Maxwellian values derived by Hollweg. It is also shown that the heat flux is best described using a form that does not directly involve the truncation speed. Furthermore, we discuss the applicability of these distribution models for the nonrelativistic case, which constrains the κ values for the standard κ distribution to values above 4. In addition, we provide the possibility to easily obtain the heat flux parameter for a given solar wind environment.

Related

  1. Laboratory Measurements of Energy Partitioning and Anomalous Electron Heating in Magnetized, Perpendicular Collisionless Shocks
    V. Valenzuela-Villaseca, S. Totorica, J. Griff-McMahon +6
    The Astrophysical JournalPeer-reviewedCC BY 4.0Full textSolar & stellar physicsCrossref
  2. Collisionless Shock Driven by a Supersonic Velocity Shear
    Kazuki Kamiido, Yutaka Ohira
    arXivPreprintCC BY 4.0Full textHigh-energy astrophysicsPlasma physicsarXiv
  3. Importance of the Resonant Cosmic-Ray Streaming Instability Upstream of Collisionless Shocks
    Bricker Ostler, Benedikt Schroer, Damiano Caprioli
    arXivPreprintarXiv licenceFull textHigh-energy astrophysicsarXiv
  4. Collisionless stationary states of a stratified plasma in an expanding magnetic tube with stochastic heating
    Luca Barbieri, Pascal Démoulin, Daniel Verscharen
    arXivPreprintCC BY 4.0Full textSolar & stellar physicsPlasma physicsarXiv
  5. A Magnetothermodynamic Theory of Energy Transport In Collisionless Plasmas
    Dominic Payne
    arXivPreprintCC BY 4.0Full textSolar & stellar physicsPlasma physicsarXiv

Cite

BibTeXRIS
BibTeX
@article{scherer2026collisionless,
  title = {{Collisionless Electron Heat Flux for the Nonequilibrium Solar Wind Plasma: Revisiting Hollweg’s Parameter}},
  author = {Klaus Scherer and Lukas Westrich and Marian Lazar and Horst Fichtner and Stefaan Poedts},
  journal = {The Astrophysical Journal},
  year = {2026},
  month = nov,
  doi = {10.3847/1538-4357/ae993f},
  url = {https://iopscience.iop.org/article/10.3847/1538-4357/ae993f},
  note = {CC BY 4.0},
}
RIS
TY  - JOUR
TI  - Collisionless Electron Heat Flux for the Nonequilibrium Solar Wind Plasma: Revisiting Hollweg’s Parameter
AU  - Klaus Scherer
AU  - Lukas Westrich
AU  - Marian Lazar
AU  - Horst Fichtner
AU  - Stefaan Poedts
PY  - 2026
DA  - 2026/11/06
JO  - The Astrophysical Journal
DO  - 10.3847/1538-4357/ae993f
UR  - https://iopscience.iop.org/article/10.3847/1538-4357/ae993f
AB  - Here, we discuss an extension of the modelling of the collisionless heat flux and the related parameter α , derived by Hollweg for a truncated Maxwellian to distributions with suprathermal tails. In the collisionless solar wind plasma, electrons and ions are described by a multitude of non-Maxwellian (nonequilibrium) velocity distributions, such as the standard, regularized κ , and Druyvesteyn distributions. We show that for these nonidealized distributions, the heat flux and the related parameter α can deviate significantly from the Maxwellian values derived by Hollweg. It is also shown that the heat flux is best described using a form that does not directly involve the truncation speed. Furthermore, we discuss the applicability of these distribution models for the nonrelativistic case, which constrains the κ values for the standard κ distribution to values above 4. In addition, we provide the possibility to easily obtain the heat flux parameter for a given solar wind environment.
SN  - 1538-4357
SN  - 0004-637X
ER  -