The Astrophysical Journal (Jan 2023)
The Structure and Origin of Switchbacks: Parker Solar Probe Observations
- Jia Huang,
- J. C. Kasper,
- L. A. Fisk,
- Davin E. Larson,
- Michael D. McManus,
- C. H. K. Chen,
- Mihailo M. Martinović,
- K. G. Klein,
- Luke Thomas,
- Mingzhe Liu,
- Bennett A. Maruca,
- Lingling Zhao,
- Yu Chen,
- Qiang Hu,
- Lan K. Jian,
- J. L. Verniero,
- Marco Velli,
- Roberto Livi,
- P. Whittlesey,
- Ali Rahmati,
- Orlando Romeo,
- Tatiana Niembro,
- Kristoff Paulson,
- M. Stevens,
- A. W. Case,
- Marc Pulupa,
- Stuart D. Bale,
- J. S. Halekas
Affiliations
- Jia Huang
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]
- J. C. Kasper
- ORCiD
- BWX Technologies, Inc. , Washington, DC 20001, USA; Climate and Space Sciences and Engineering, University of Michigan , Ann Arbor, MI 48109, USA
- L. A. Fisk
- ORCiD
- Climate and Space Sciences and Engineering, University of Michigan , Ann Arbor, MI 48109, USA
- Davin E. Larson
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]
- Michael D. McManus
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]
- C. H. K. Chen
- ORCiD
- School of Physics and Astronomy, Queen Mary University of London , London E1 4NS, UK
- Mihailo M. Martinović
- ORCiD
- Lunar and Planetary Laboratory, University of Arizona , Tucson, AZ 85719, USA; LESIA, Observatoire de Paris, Université PSL , CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, F-92195 Meudon, France
- K. G. Klein
- ORCiD
- Lunar and Planetary Laboratory, University of Arizona , Tucson, AZ 85719, USA
- Luke Thomas
- Climate and Space Sciences and Engineering, University of Michigan , Ann Arbor, MI 48109, USA
- Mingzhe Liu
- ORCiD
- LESIA, Observatoire de Paris, Université PSL , CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, F-92195 Meudon, France
- Bennett A. Maruca
- ORCiD
- Department of Physics and Astronomy, University of Delaware , Newark, DE 19716, USA; Bartol Research Institute, University of Delaware , Newark, DE 19716, USA
- Lingling Zhao
- ORCiD
- Department of Space Science and CSPAR, The University of Alabama in Huntsville , Huntsville, AL 35805, USA
- Yu Chen
- ORCiD
- Department of Space Science and CSPAR, The University of Alabama in Huntsville , Huntsville, AL 35805, USA
- Qiang Hu
- ORCiD
- Department of Space Science and CSPAR, The University of Alabama in Huntsville , Huntsville, AL 35805, USA
- Lan K. Jian
- ORCiD
- Heliophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- J. L. Verniero
- ORCiD
- Heliophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- Marco Velli
- ORCiD
- Department of Earth, Planetary and Space Sciences, University of California , Los Angeles, CA 90095, USA
- Roberto Livi
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]
- P. Whittlesey
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]
- Ali Rahmati
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]
- Orlando Romeo
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]
- Tatiana Niembro
- ORCiD
- Smithsonian Astrophysical Observatory , Cambridge, MA 02138, USA
- Kristoff Paulson
- ORCiD
- Smithsonian Astrophysical Observatory , Cambridge, MA 02138, USA
- M. Stevens
- ORCiD
- Smithsonian Astrophysical Observatory , Cambridge, MA 02138, USA
- A. W. Case
- ORCiD
- Smithsonian Astrophysical Observatory , Cambridge, MA 02138, USA
- Marc Pulupa
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]
- Stuart D. Bale
- ORCiD
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA ; [email protected]; School of Physics and Astronomy, Queen Mary University of London , London E1 4NS, UK; Physics Department, University of California , Berkeley, CA 94720-7300, USA; The Blackett Laboratory, Imperial College London , London, SW7 2AZ, UK
- J. S. Halekas
- ORCiD
- Department of Physics and Astronomy, University of Iowa , Iowa City, IA 52242, USA
- DOI
- https://doi.org/10.3847/1538-4357/acd17e
- Journal volume & issue
-
Vol. 952,
no. 1
p. 33
Abstract
Switchbacks are rapid magnetic field reversals that last from seconds to hours. Current Parker Solar Probe (PSP) observations pose many open questions in regard to the nature of switchbacks. For example, are they stable as they propagate through the inner heliosphere, and how are they formed? In this work, we aim to investigate the structure and origin of switchbacks. In order to study the stability of switchbacks, we suppose the small-scale current sheets therein are generated by magnetic braiding, and they should work to stabilize the switchbacks. With more than 1000 switchbacks identified with PSP observations in seven encounters, we find many more current sheets inside than outside switchbacks, indicating that these microstructures should work to stabilize the S-shape structures of switchbacks. Additionally, we study the helium variations to trace the switchbacks to their origins. We find both helium-rich and helium-poor populations in switchbacks, implying that the switchbacks could originate from both closed and open magnetic field regions in the Sun. Moreover, we observe that the alpha-proton differential speeds also show complex variations as compared to the local Alfvén speed. The joint distributions of both parameters show that low helium abundance together with low differential speed is the dominant state in switchbacks. The presence of small-scale current sheets in switchbacks along with the helium features are in line with the hypothesis that switchbacks could originate from the Sun via interchange reconnection process. However, other formation mechanisms are not excluded.
Keywords
