The magnetic structure of surges in small-scale emerging flux regions

David MacTaggart, S. L. Guglielmino, A. L. Haynes, R. Simitev, F. Zuccarello

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Aims. We investigate the relationship between surges and magnetic reconnection during the emergence of small-scale active regions. In particular, to examine how the large-scale geometry of the magnetic field, shaped by different phases of reconnection, guides the flowing of surges.

Methods. We present three flux emergence models. The first model, and the simplest, consists of a region emerging into a horizontal ambient field that is initially parallel to the top of the emerging region. The second model is the same as the first but with an extra smaller emerging region which perturbs the main region. This is added to create a more complex magnetic topology and to test how this complicates the development of surges compared to the first model. The last model has a non-uniform ambient magnetic field to model the effects of emergence near a sunspot field and impose asymmetry on the system through the ambient magnetic field. At each stage, we trace the magnetic topology to identify the locations of reconnection. This allows for field lines to be plotted from different topological regions, highlighting how their geometry affects the development of surges.

Results. In the first model, we identify distinct phases of reconnection. Each phase is associated with a particular geometry for the magnetic field and this determines the paths of the surges. The second model follows a similar pattern to the first but with a more complex magnetic topology and extra eruptions. The third model highlights how an asymmetric ambient field can result in preferred locations for reconnection, subsequently guiding the direction of surges.

Conclusions. Each of the identified phases highlights the close connection between magnetic field geometry, reconnection and the flow of surges. These phases can now be detected observationally and may prove to be key signatures in determining whether or not an emerging region will produce a large-scale (CME-type) eruption.
Original languageEnglish
Article number4
Number of pages12
JournalAstronomy & Astrophysics
Volume576
Early online date13 Mar 2015
DOIs
Publication statusPublished - Apr 2015

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emerging
magnetic fields
topology
geometry
volcanic eruptions
sunspots
signatures
asymmetry

Cite this

MacTaggart, D., Guglielmino, S. L., Haynes, A. L., Simitev, R., & Zuccarello, F. (2015). The magnetic structure of surges in small-scale emerging flux regions. Astronomy & Astrophysics, 576, [4]. https://doi.org/10.1051/0004-6361/201424646
MacTaggart, David ; Guglielmino, S. L. ; Haynes, A. L. ; Simitev, R. ; Zuccarello, F. / The magnetic structure of surges in small-scale emerging flux regions. In: Astronomy & Astrophysics. 2015 ; Vol. 576.
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MacTaggart, D, Guglielmino, SL, Haynes, AL, Simitev, R & Zuccarello, F 2015, 'The magnetic structure of surges in small-scale emerging flux regions', Astronomy & Astrophysics, vol. 576, 4. https://doi.org/10.1051/0004-6361/201424646

The magnetic structure of surges in small-scale emerging flux regions. / MacTaggart, David; Guglielmino, S. L.; Haynes, A. L.; Simitev, R.; Zuccarello, F.

In: Astronomy & Astrophysics, Vol. 576, 4, 04.2015.

Research output: Contribution to journalArticle

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AU - Zuccarello, F.

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N2 - Aims. We investigate the relationship between surges and magnetic reconnection during the emergence of small-scale active regions. In particular, to examine how the large-scale geometry of the magnetic field, shaped by different phases of reconnection, guides the flowing of surges.Methods. We present three flux emergence models. The first model, and the simplest, consists of a region emerging into a horizontal ambient field that is initially parallel to the top of the emerging region. The second model is the same as the first but with an extra smaller emerging region which perturbs the main region. This is added to create a more complex magnetic topology and to test how this complicates the development of surges compared to the first model. The last model has a non-uniform ambient magnetic field to model the effects of emergence near a sunspot field and impose asymmetry on the system through the ambient magnetic field. At each stage, we trace the magnetic topology to identify the locations of reconnection. This allows for field lines to be plotted from different topological regions, highlighting how their geometry affects the development of surges.Results. In the first model, we identify distinct phases of reconnection. Each phase is associated with a particular geometry for the magnetic field and this determines the paths of the surges. The second model follows a similar pattern to the first but with a more complex magnetic topology and extra eruptions. The third model highlights how an asymmetric ambient field can result in preferred locations for reconnection, subsequently guiding the direction of surges. Conclusions. Each of the identified phases highlights the close connection between magnetic field geometry, reconnection and the flow of surges. These phases can now be detected observationally and may prove to be key signatures in determining whether or not an emerging region will produce a large-scale (CME-type) eruption.

AB - Aims. We investigate the relationship between surges and magnetic reconnection during the emergence of small-scale active regions. In particular, to examine how the large-scale geometry of the magnetic field, shaped by different phases of reconnection, guides the flowing of surges.Methods. We present three flux emergence models. The first model, and the simplest, consists of a region emerging into a horizontal ambient field that is initially parallel to the top of the emerging region. The second model is the same as the first but with an extra smaller emerging region which perturbs the main region. This is added to create a more complex magnetic topology and to test how this complicates the development of surges compared to the first model. The last model has a non-uniform ambient magnetic field to model the effects of emergence near a sunspot field and impose asymmetry on the system through the ambient magnetic field. At each stage, we trace the magnetic topology to identify the locations of reconnection. This allows for field lines to be plotted from different topological regions, highlighting how their geometry affects the development of surges.Results. In the first model, we identify distinct phases of reconnection. Each phase is associated with a particular geometry for the magnetic field and this determines the paths of the surges. The second model follows a similar pattern to the first but with a more complex magnetic topology and extra eruptions. The third model highlights how an asymmetric ambient field can result in preferred locations for reconnection, subsequently guiding the direction of surges. Conclusions. Each of the identified phases highlights the close connection between magnetic field geometry, reconnection and the flow of surges. These phases can now be detected observationally and may prove to be key signatures in determining whether or not an emerging region will produce a large-scale (CME-type) eruption.

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