Evolution of switchbacks in the inner heliosphere
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
We analyze magnetic field data from the first six encounters of Parker Solar Probe, three Helios fast streams and two Ulysses south polar passes covering heliocentric distances 0.1 ≲ R ≲ 3 au. We use this data set to statistically determine the evolution of switchbacks of different periods and amplitudes with distance from the Sun. We compare the radial evolution of magnetic field variances with that of the mean square amplitudes of switchbacks, and quantify the radial evolution of the cumulative counts of switchbacks per kilometer. We find that the amplitudes of switchbacks decrease faster than the overall turbulent fluctuations, in a way consistent with the radial decrease of the mean magnetic field. This could be the result of a saturation of amplitudes and may be a signature of decay processes of large amplitude Alfvénic fluctuations in the solar wind. We find that the evolution of switchback occurrence in the solar wind is scale dependent: the fraction of longer-duration switchbacks increases with radial distance, whereas it decreases for shorter switchbacks. This implies that switchback dynamics is a complex process involving both decay and in situ generation in the inner heliosphere. We confirm that switchbacks can be generated by the expansion, although other types of switchbacks generated closer to the Sun cannot be ruled out.
Date Issued
2021-10-01
Date Acceptance
2021-09-13
Citation
Letters of the Astrophysical Journal, 2021, 919 (2), pp.1-7
ISSN
2041-8205
Publisher
American Astronomical Society
Start Page
1
End Page
7
Journal / Book Title
Letters of the Astrophysical Journal
Volume
919
Issue
2
Copyright Statement
© 2021. The American Astronomical Society. All rights reserved.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000703272500001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
SOLAR-WIND
RADIAL EVOLUTION
PARAMETRIC DECAY
ALFVEN WAVES
SPEED
Publication Status
Published
Article Number
ARTN L31
Date Publish Online
2021-10-04