Skip to Main content Skip to Navigation
New interface
Journal articles

The Interplay Between Ambipolar Electric Field and Coulomb Collisions in the Solar Wind Acceleration Region

Abstract : The solar wind protons are accelerated to supersonic velocities within the distance of 10 solar radii from the Sun, as a consequence of a complex physical mechanism including particle kinetic effects as well as the field particle energy and momentum exchange. We use a numerical kinetic model of the solar wind, accounting for Coulomb collisions (BiCoP), and model a solar wind accelerated only by the ambipolar electrostatic filed (E) arising due to the difference in mass between electron and proton, and assuring quasi neutrality and zero current. We study the effect E, which was found to be on the order of Dreicer electric field (ED) (Dreicer, 1959), has on the resulting electron velocity distribution functions. The strahl electron radial evolution is represented by means of its pitch angle width (PAW), and the strahl parallel temperature (Ts,‖). A continuous transition between collisional and weakly collisional regime results in broader PAW, compared to the single exobase prediction imposed by the exospheric models. Collisions were found to scatter strahl electrons below 250 eV, which in turn has an effect on the measured Ts,‖. A slight increase was found in Ts,‖ with radial distance, and was stronger for the more collisional run. We estimate that the coronal electron temperature inferred from the observations of Ts,‖ in the solar wind, would be overestimated for between 8% and 15%.
Document type :
Journal articles
Complete list of metadata

https://hal-insu.archives-ouvertes.fr/insu-03713791
Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Saturday, August 6, 2022 - 1:42:28 PM
Last modification on : Saturday, August 6, 2022 - 1:42:30 PM
Long-term archiving on: : Monday, November 7, 2022 - 6:11:28 PM

File

JGR Space Physics - 2021 - Ber...
Publisher files allowed on an open archive

Licence

Copyright

Identifiers

Citation

L. Berčič, S. Landi, M. Maksimović. The Interplay Between Ambipolar Electric Field and Coulomb Collisions in the Solar Wind Acceleration Region. Journal of Geophysical Research: Space Physics, 2021, 126, ⟨10.1029/2020JA028864⟩. ⟨insu-03713791⟩

Share

Metrics

Record views

23

Files downloads

3