Journal article
A Solar Source of Alfvenic Magnetic Field Switchbacks: In Situ Remnants of Magnetic Funnels on Supergranulation Scales
The Astrophysical journal, Vol.923(2), p.174
12/01/2021
DOI: 10.3847/1538-4357/ac2d8c
Abstract
One of the striking observations from the Parker Solar Probe (PSP) spacecraft is the prevalence in the inner heliosphere of large amplitude, Alfvenic magnetic field reversals termed switchbacks. These delta B-R/B similar to O(i) fluctuations occur over a range of timescales and in patches separated by intervals of quiet, radial magnetic field. We use measurements from PSP to demonstrate that patches of switchbacks are localized within the extensions of plasma structures originating at the base of the corona. These structures are characterized by an increase in alpha particle abundance, Mach number, plasma beta and pressure, and by depletions in the magnetic field magnitude and electron temperature. These intervals are in pressure balance, implying stationary spatial structure, and the field depressions are consistent with overexpanded flux tubes. The structures are asymmetric in Carrington longitude with a steeper leading edge and a small (similar to 1 degrees) edge of hotter plasma and enhanced magnetic field fluctuations. Some structures contain suprathermal ions to similar to 85 keV that we argue are the energetic tail of the solar wind alpha population. The structures are separated in longitude by angular scales associated with supergranulation. This suggests that these switchbacks originate near the leading edge of the diverging magnetic field funnels associated with the network magnetic field-the primary wind sources. We propose an origin of the magnetic field switchbacks, hot plasma and suprathermals, alpha particles in interchange reconnection events just above the solar transition region and our measurements represent the extended regions of a turbulent outflow exhaust.
Details
- Title: Subtitle
- A Solar Source of Alfvenic Magnetic Field Switchbacks: In Situ Remnants of Magnetic Funnels on Supergranulation Scales
- Creators
- S. D. Bale - University of California, BerkeleyT. S. Horbury - Imperial College LondonM. Velli - Univ Calif Los Angeles, Earth Planetary & Space Sci, Los Angeles, CA 90095 USAM. I. Desai - Southwest Research InstituteJ. S. Halekas - University of IowaM. D. McManus - University of California, BerkeleyO. Panasenco - Advanced HeliophysicsS. T. Badman - University of California, BerkeleyT. A. Bowen - Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USAB. D. G. Chandran - University of New HampshireJ. F. Drake - University of Maryland, College ParkJ. C. Kasper - University of MichiganR. Laker - Imperial College LondonA. Mallet - University of California, BerkeleyL. Matteini - Imperial College LondonT. D. Phan - University of California, BerkeleyN. E. Raouafi - Johns Hopkins University Applied Physics LaboratoryJ. Squire - University of OtagoL. D. Woodham - Imperial College LondonT. Woolley - Imperial College London
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.923(2), p.174
- DOI
- 10.3847/1538-4357/ac2d8c
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Publisher
- IOP Publishing Ltd
- Number of pages
- 12
- Grant note
- 80NSSC20K1829; NNX17AI18G; 80NSSC19K0829 / NASA; National Aeronautics & Space Administration (NASA) ST/S000364/1 / UK STFC; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) PHY2109083 / NSF; National Science Foundation (NSF) 80NSSC20K0604 / HERMES DRIVE NASA Science Center grant Imperial College President's scholarship NNN06AA01C / NASA's Living with a Star (LWS) program 80NSSC20K0627 / NASA DRIVE Science Center on Solar Flare Energy Release RDF-U00180 / Royal Society Te Aparangi NZ through Rutherford Discovery Fellowship; Royal Society of New Zealand
- Language
- English
- Date published
- 12/01/2021
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428823802771
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