Magnetic Structures at the Boundary of the Closed Corona: Interpretation of S-Web Arcs

Scott, Roger B.; Pontin, D. I.; Yeates, Anthony R.; Wyper, P. F.; Higginson, A. K.

doi:10.3847/1538-4357/aaed2b

Cited by 22 publications

(16 citation statements)

References 45 publications

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“…The newly reconnected flux is analogous to the satellite coronal hole formed by the SN configuration but differs in that its footprint on the photosphere is surrounded entirely by closed flux beneath the HS; its only connection to the polar coronal hole is along the spine field lines of N C . This is structurally identical to the "detached" coronal holes discussed by Titov et al (2011) andScott et al (2018).…”

Section: Topological Evolutionsupporting

confidence: 59%

“…More recently, Scott et al (2018) performed a careful analysis of S-Web arcs in a potential-field extrapolation and reached a similar conclusion regarding the typical composition of the underlying magnetic field. As in other studies, these authors identified the structures within the S-Web by evaluating Q ⊥ , which they combined with knowledge of the domain connectivity to form slog 10 Q ⊥ = ±log 10 Q ⊥ .…”

Section: Static Models Of S-web Structuresmentioning

confidence: 59%

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The Dynamic Formation of Pseudostreamers

Scott

Pontin

Antiochos

et al. 2021

ApJ

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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.

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Section: Topological Evolutionsupporting

confidence: 59%

Section: Static Models Of S-web Structuresmentioning

confidence: 59%

The Dynamic Formation of Pseudostreamers

Scott

Pontin

Antiochos

et al. 2021

ApJ

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“…Theoretically, the boundary between open and closed magnetic flux is presumed to define separatrices associated with the heliospheric current sheet (i.e., the global helmet streamer) as well as the plethora of coronal magnetic nulls and (to a lesser extent) bald patches (Titov et al 2011;Platten et al 2014;Scott et al 2018Scott et al , 2019. In order to assess the implications of interchange reconnection for the solar wind, we need to understand how the process evolves at these various structures, and how it relates to different features of the observations (Viall & Borovsky 2020).…”

Section: Introductionmentioning

confidence: 99%

Effects of Pseudostreamer Boundary Dynamics on Heliospheric Field and Wind

Aslanyan

Pontin

Wyper

et al. 2021

ApJ

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Interchange reconnection has been proposed as a mechanism for the generation of the slow solar wind, and a key contributor to determining its characteristic qualities. In this paper we study the implications of interchange reconnection for the structure of the plasma and field in the heliosphere. We use the Adaptively Refined Magnetohydrodynamic Solver to simulate the coronal magnetic evolution in a coronal topology containing both a pseudostreamer and helmet streamer. We begin with a geometry containing a low-latitude coronal hole that is separated from the main polar coronal hole by a pseudostreamer. We drive the system by imposing rotating flows at the solar surface within and around the low-latitude coronal hole, which leads to a corrugation (at low altitudes) of the separatrix surfaces that separate open from closed magnetic flux. Interchange reconnection is induced both at the null points and separators of the pseudostreamer, and at the global helmet streamer. We demonstrate that a preferential occurrence of interchange reconnection in the "lanes" between our driving cells leads to a filamentary pattern of newly opened flux in the heliosphere. These flux bundles connect to but extend far from the separatrixweb (S-Web) arcs at the source surface. We propose that the pattern of granular and supergranular flows on the photosphere should leave an observable imprint in the heliosphere.

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“…More complex are the pseudostreamers that form above the long tails of minority polarity, stretched out by differential rotation and meridional flow, that are associated with decaying active regions. These often involve multiple nulls and/or bald patches along the length of the pseudostreamer, and they are so large that their proximity to the nearby helmet-streamer boundary also must be taken into account (Titov et al 2011(Titov et al , 2012Scott et al 2018Scott et al , 2019Masson et al 2019).…”

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confidence: 99%

A Model for the Coupled Eruption of a Pseudostreamer and Helmet Streamer

Wyper

Antiochos

DeVore

et al. 2021

ApJ

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A highly important aspect of solar activity is the coupling between eruptions and the surrounding coronal magnetic field topology, which determines the trajectory and morphology of the event and can even lead to sympathetic eruptions from multiple sources. In this paper, we report on a numerical simulation of a new type of coupled eruption, in which a coronal jet initiated by a large pseudostreamer filament eruption triggers a streamer-blowout coronal mass ejection (CME) from the neighboring helmet streamer. Our configuration has a large opposite-polarity region positioned between the polar coronal hole and a small equatorial coronal hole, forming a pseudostreamer flanked by the coronal holes and the helmet streamer. Further out, the pseudostreamer stalk takes the shape of an extended arc in the heliosphere. We energize the system by applying photospheric shear along a section of the polarity inversion line within the pseudostreamer. The resulting sheared-arcade filament channel develops a flux rope that eventually erupts as a classic coronal-hole-type jet. However, the enhanced breakout reconnection above the channel as the jet is launched progresses into the neighboring helmet streamer, partially launching the jet along closed helmet streamer field lines and blowing out the streamer top to produce a classic bubble-like CME. This CME is strongly deflected from the jet’s initial trajectory and contains a mixture of open and closed magnetic field lines. We present the detailed dynamics of this new type of coupled eruption, its underlying mechanisms, and the implications of this work for the interpretation of in situ and remote-sensing observations.

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Magnetic Structures at the Boundary of the Closed Corona: Interpretation of S-Web Arcs

Cited by 22 publications

References 45 publications

The Dynamic Formation of Pseudostreamers

The Dynamic Formation of Pseudostreamers

Effects of Pseudostreamer Boundary Dynamics on Heliospheric Field and Wind

A Model for the Coupled Eruption of a Pseudostreamer and Helmet Streamer

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