Publication detail

Coronal Magnetic Field Topology from Total Solar Eclipse Observations

BOE, B. HABBAL, S. DRUCKMÜLLER, M.

Original Title

Coronal Magnetic Field Topology from Total Solar Eclipse Observations

English Title

Coronal Magnetic Field Topology from Total Solar Eclipse Observations

Type

journal article in Web of Science

Language

en

Original Abstract

Measuring the global magnetic field of the solar corona remains exceptionally challenging. The fine-scale density structures observed in white-light images taken during total solar eclipses are currently the best proxies for inferring the magnetic field direction in the corona from the solar limb out to several solar radii (R). We present, for the first time, the topology of the coronal magnetic field continuously between 1 and 6 R, as quantitatively inferred with the rolling Hough transform for 14 unique eclipse coronae that span almost two complete solar cycles. We find that the direction of the coronal magnetic field does not become radial until at least 3 R, with a high variance between 1.5 and 3 R at different latitudes and phases of the solar cycle. We find that the most nonradial coronal field topologies occur above regions with weaker magnetic field strengths in the photosphere, while stronger photospheric fields are associated with highly radial field lines in the corona. In addition, we find an abundance of field lines that extend continuously from the solar surface out to several solar radii at all latitudes, regardless of the presence of coronal holes. These results have implications for testing and constraining coronal magnetic field models, and for linking in situ solar wind measurements to their sources at the Sun.

English abstract

Measuring the global magnetic field of the solar corona remains exceptionally challenging. The fine-scale density structures observed in white-light images taken during total solar eclipses are currently the best proxies for inferring the magnetic field direction in the corona from the solar limb out to several solar radii (R). We present, for the first time, the topology of the coronal magnetic field continuously between 1 and 6 R, as quantitatively inferred with the rolling Hough transform for 14 unique eclipse coronae that span almost two complete solar cycles. We find that the direction of the coronal magnetic field does not become radial until at least 3 R, with a high variance between 1.5 and 3 R at different latitudes and phases of the solar cycle. We find that the most nonradial coronal field topologies occur above regions with weaker magnetic field strengths in the photosphere, while stronger photospheric fields are associated with highly radial field lines in the corona. In addition, we find an abundance of field lines that extend continuously from the solar surface out to several solar radii at all latitudes, regardless of the presence of coronal holes. These results have implications for testing and constraining coronal magnetic field models, and for linking in situ solar wind measurements to their sources at the Sun.

Keywords

Solar corona; Solar magnetic fields; Solar eclipses; Solar coronal plumes; Solar coronal streamers; Solar cycle; Solar coronal holes; Solar optical telescopes; Solar wind

Released

03.06.2020

Publisher

IOP PUBLISHING LTD

Location

BRISTOL

Pages from

123

Pages to

137

Pages count

14

URL

Documents

BibTex


@article{BUT164323,
  author="Benjamin {Boe} and Shadia Rifai {Habbal} and Miloslav {Druckmüller}",
  title="Coronal Magnetic Field Topology from Total Solar Eclipse Observations",
  annote="Measuring the global magnetic field of the solar corona remains exceptionally challenging. The fine-scale density structures observed in white-light images taken during total solar eclipses are currently the best proxies for inferring the magnetic field direction in the corona from the solar limb out to several solar radii (R). We present, for the first time, the topology of the coronal magnetic field continuously between 1 and 6 R, as quantitatively inferred with the rolling Hough transform for 14 unique eclipse coronae that span almost two complete solar cycles. We find that the direction of the coronal magnetic field does not become radial until at least 3 R, with a high variance between 1.5 and 3 R at different latitudes and phases of the solar cycle. We find that the most nonradial coronal field topologies occur above regions with weaker magnetic field strengths in the photosphere, while stronger photospheric fields are associated with highly radial field lines in the corona. In addition, we find an abundance of field lines that extend continuously from the solar surface out to several solar radii at all latitudes, regardless of the presence of coronal holes. These results have implications for testing and constraining coronal magnetic field models, and for linking in situ solar wind measurements to their sources at the Sun.",
  address="IOP PUBLISHING LTD",
  chapter="164323",
  doi="10.3847/1538-4357/ab8ae6",
  howpublished="print",
  institution="IOP PUBLISHING LTD",
  number="2",
  volume="895",
  year="2020",
  month="june",
  pages="123--137",
  publisher="IOP PUBLISHING LTD",
  type="journal article in Web of Science"
}