Vortex flow in the solar photosphere

Brandt, Peter; Scharmer, G.; Ferguson, S. H.; Shine, R. A.; Tarbell, T. D.; Title, A. M.

doi:10.1038/335238a0

Cited by 168 publications

(126 citation statements)

References 12 publications

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“…Initially, the vortical motions in quiet-Sun regions were detected on a large scale of ∼5 Mm (Brandt et al 1988). With the development of instrumentation it became possible to observe small-scale swirls in the photosphere (Bonet et al 2008; with size <0.5 Mm) and also in the chromosphere with size ∼1.5 Mm (Wedemeyer-Böhm & Rouppe van der Voort 2009).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Mechanism of Spontaneous Formation of Stable Magnetic Structures on the Sun

Kitiashvili

Kosovichev

Wray

et al. 2010

ApJ

102

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One of the puzzling features of solar magnetism is formation of long-living compact magnetic structures, such as sunspots and pores, in the highly turbulent upper layer of the solar convective zone. We use realistic radiative three-dimensional MHD simulations to investigate the interaction between magnetic field and turbulent convection. In the simulations, a weak vertical uniform magnetic field is imposed in a region of fully developed granular convection, and the total magnetic flux through the top and bottom boundaries is kept constant. The simulation results reveal a process of spontaneous formation of stable magnetic structures, which may be a key to understanding the magnetic self-organization on the Sun and formation of pores and sunspots. This process consists of two basic steps: (1) formation of small-scale filamentary magnetic structures associated with concentrations of vorticity and whirlpool-type motions, and (2) merging of these structures due to the vortex attraction, caused by converging downdrafts around magnetic concentration below the surface. In the resulting large-scale structure maintained by the converging plasma motions, the magnetic field strength reaches ∼1.5 kG at the surface and ∼6 kG in the interior, and the surface structure resembles solar pores. The magnetic structure remains stable for the whole simulation run of several hours with no sign of decay.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Mechanism of Spontaneous Formation of Stable Magnetic Structures on the Sun

Kitiashvili

Kosovichev

Wray

et al. 2010

ApJ

102

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“…Signatures of photospheric vortex flows have also been observed on even larger scales such as supergranular junctions (Attie et al 2009). Vortical motions in the solar photosphere were studied by simulations (Zirker 1993, and references herein) and are understood to play an important role in the evolution of magnetic footpoints and heating in the upper solar atmosphere (Brandt et al 1988;Wang et al 1995). Here we describe a vortex motion in the solar photosphere that persists for about 20 min.…”

Section: Introductionmentioning

confidence: 96%

Evidence of small-scale magnetic concentrations dragged by vortex motion of solar photospheric plasma

Balmaceda

Domínguez

Palacios³

et al. 2010

A&A

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Vortex-type motions have been measured by tracking bright points in high-resolution observations of the solar photosphere. These small-scale motions are thought to be determinant in the evolution of magnetic footpoints and their interaction with plasma and therefore likely to play a role in heating the upper solar atmosphere by twisting magnetic flux tubes. We report the observation of magnetic concentrations being dragged towards the center of a convective vortex motion in the solar photosphere from highresolution ground-based and space-borne data. We describe this event by analyzing a series of images at different solar atmospheric layers. By computing horizontal proper motions, we detect a vortex whose center appears to be the draining point for the magnetic concentrations detected in magnetograms and well-correlated with the locations of bright points seen in G-band and CN images.

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“…At granular scales, the flow is much faster than the supergranular flow, up to more than 1000 m s −1 (Berger et al 1998). It contains a significant numbers of vortices, which have already been observed at smaller scale by Brandt et al (1988) and Bonet et al (2010). Thus, down-scaling the sketch in Fig.…”

Section: Prospects For Future Studiesmentioning

confidence: 99%

Relationship between supergranulation flows, magnetic cancellation and network flares

Attié

Innes

Solanki

et al. 2016

A&A

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Context. Photospheric flows create a network of often mixed-polarity magnetic field in the quiet Sun, where small-scale eruptions and network flares are commonly seen. Aims. The aim of this paper is (1) to describe the characteristics of the flows that lead to these energy releases, (2) to quantify the energy build up due to photospheric flows acting on the magnetic field, and (3) to assess its contribution to the energy of small-scale, short-lived X-ray flares in the quiet Sun. Methods. We used photospheric and X-ray data from the SoHO and Hinode spacecraft combined with tracking algorithms to analyse the evolution of five network flares. The energy of the X-ray emitting thermal plasma is compared with an estimate of the energy built up due to converging and sheared flux. Results. Quiet-Sun network flares occur above sites of converging opposite-polarity magnetic flux that are often found on the outskirts of network cell junctions, sometimes with observable vortex-like motion. In all studied flares the thermal energy was more than an order of magnitude higher than the magnetic free energy of the converging flux model. The energy in the sheared field was always higher than in the converging flux but still lower than the thermal energy. Conclusions. X-ray network flares occur at sites of magnetic energy dissipation. The energy is probably built up by supergranular flows causing systematic shearing of the magnetic field. This process appears more efficient near the junction of the network lanes. Since this work relies on 11 case studies, our results call for a follow-up statistical analysis to test our hypothesis throughout the quiet Sun.

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Vortex flow in the solar photosphere

Cited by 168 publications

References 12 publications

Mechanism of Spontaneous Formation of Stable Magnetic Structures on the Sun

Mechanism of Spontaneous Formation of Stable Magnetic Structures on the Sun

Evidence of small-scale magnetic concentrations dragged by vortex motion of solar photospheric plasma

Relationship between supergranulation flows, magnetic cancellation and network flares

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