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The Dynamic Formation of Pseudostreamers
Author | Scott, Roger; Pontin, David; Antiochos, Spiro; DeVore, Richard; Wyper, Peter; |
Keywords | Solar Physics; Solar magnetic reconnection; Solar wind; 1476; 1504; 1534; Parker Data Used |
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. |
Year of Publication | 2021 |
Journal | The Astrophysical Journal |
Volume | 913 |
Number of Pages | 64 |
Section | |
Date Published | 05/2021 |
ISBN | |
URL | https://ui.adsabs.harvard.edu/abs/2021ApJ...913...64S |
DOI | 10.3847/1538-4357/abec4f |