Enhanced proton parallel temperature inside patches of switchbacks in the inner heliosphere
File(s)Woodham_A&A_2020_Accepted.pdf (2.2 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
Context. Switchbacks are discrete angular deflections in the solar wind magnetic field that have been observed throughout the helio-sphere. Recent observations by Parker Solar Probe(PSP) have revealed the presence of patches of switchbacks on the scale of hours to days, separated by ‘quieter’ radial fields. Aims. We aim to further diagnose the origin of these patches using measurements of proton temperature anisotropy that can illuminate possible links to formation processes in the solar corona. Methods. We fit 3D bi-Maxwellian functions to the core of proton velocity distributions measured by the SPAN-Ai instrument onboard PSP to obtain the proton parallel, Tp,‖, and perpendicular, Tp,⊥, temperature. Results. We show that the presence of patches is highlighted by a transverse deflection in the flow and magnetic field away from the radial direction. These deflections are correlated with enhancements in Tp,‖, while Tp,⊥remains relatively constant. Patches sometimes exhibit small proton and electron density enhancements. Conclusions. We interpret that patches are not simply a group of switchbacks, but rather switchbacks are embedded within a larger-scale structure identified by enhanced Tp,‖that is distinct from the surrounding solar wind. We suggest that these observations are consistent with formation by reconnection-associated mechanisms in the corona.
Date Issued
2021-06-02
Date Acceptance
2020-10-12
Citation
Astronomy and Astrophysics: a European journal, 2021, 650, pp.1-7
ISSN
0004-6361
Publisher
EDP Sciences
Start Page
1
End Page
7
Journal / Book Title
Astronomy and Astrophysics: a European journal
Volume
650
Copyright Statement
© ESO 2021
Sponsor
Science and Technology Facilities Council (STFC)
The Leverhulme Trust
The Royal Society
Identifier
https://www.aanda.org/articles/aa/full_html/2021/06/aa39415-20/aa39415-20.html
Grant Number
ST/S000364/1
VP2-2017-029
URF\R1\180671
Subjects
astro-ph.SR
astro-ph.SR
physics.space-ph
0201 Astronomical and Space Sciences
Astronomy & Astrophysics
Publication Status
Published
Date Publish Online
2021-06-02