The Dynamic Formation of Pseudostreamers

Scott, Roger B.; Pontin, David I.; Antiochos, Spiro K.; DeVore, C. Richard; Wyper, Peter F.

Abstract

Streamers and pseudostreamers structure the corona at the largest scales, as seen in both eclipse and coronagraph white-light images. Their inverted-goblet appearance encloses broad coronal loops at the Sun and tapers to a narrow radial stalk away from the star. The streamer associated with the global solar dipole magnetic field is long-lived, predominantly contains a single arcade of nested loops within it, and separates opposite-polarity interplanetary magnetic fields with the heliospheric current sheet (HCS) anchored at its apex. Pseudostreamers, on the other hand, are transient, enclose double arcades of nested loops, and separate like-polarity fields with a dense plasma sheet. We use numerical magnetohydrodynamic simulations to calculate, for the first time, the formation of pseudostreamers in response to photospheric magnetic-field evolution. Convective transport of a minority-polarity flux concentration, initially positioned under one side of a streamer, through the streamer boundary into the adjacent preexisting coronal hole forms the pseudostreamer. Interchange magnetic reconnection at the overlying coronal null point(s) governs the development of the pseudostreamer above—and of a new satellite coronal hole behind—the moving minority polarity. The reconnection dynamics liberate coronal-loop plasma that can escape into the heliosphere along so-called separatrix-web ("S-Web") arcs, which reach far from the HCS and the solar equatorial plane, and can explain the origin of high-latitude slow solar wind. We describe the implications of our results for in situ and remote-sensing observations of the corona and heliosphere as obtained, most recently, by Parker Solar Probe and Solar Orbiter.

Citation

Scott, R. B., Pontin, D. I., Antiochos, S. K., DeVore, C. R., & Wyper, P. F. (2021). The Dynamic Formation of Pseudostreamers. Astrophysical Journal, 913(1), Article 64. https://doi.org/10.3847/1538-4357/abec4f

• Journal Article Type: Article
• Online Publication Date: May 25, 2021
• Publication Date: May 20, 2021
• Deposit Date: Jun 14, 2021
• Publicly Available Date: Jun 14, 2021
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 913
• Issue: 1
• Article Number: 64
• DOI: https://doi.org/10.3847/1538-4357/abec4f
• Public URL: https://durham-repository.worktribe.com/output/1274079