Modeling the sun's small scale global photospheric magnetic field

K. A. Meyer (Lead / Corresponding author), D. H. Mackay

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
101 Downloads (Pure)


We present a new model for the Sun's global photospheric magnetic field during a deep minimum of activity, in which no active regions emerge. The emergence and subsequent evolution of small-scale magnetic features across the full solar surface is simulated, subject to the influence of a global supergranular flow pattern. Visually, the resulting simulated magnetograms reproduce the typical structure and scale observed in quiet Sun magnetograms. Quantitatively, the simulation quickly reaches a steady state, resulting in a mean field and flux distribution that are in good agreement with those determined from observations. A potential coronal magnetic field is extrapolated from the simulated full Sun magnetograms to consider the implications of such a quiet photospheric magnetic field on the corona and inner heliosphere. The bulk of the coronal magnetic field closes very low down, in short connections between small-scale features in the simulated magnetic network. Just 0.1% of the photospheric magnetic flux is found to be open at 2.5 R, around 10-100 times less than that determined for typical Helioseismic and Magnetic Imager synoptic map observations. If such conditions were to exist on the Sun, this would lead to a significantly weaker interplanetary magnetic field than is currently observed, and hence a much higher cosmic ray flux at Earth.

Original languageEnglish
Article number160
Pages (from-to)1-13
Number of pages13
JournalAstrophysical Journal
Issue number2
Early online date19 Oct 2016
Publication statusPublished - 20 Oct 2016


  • Sun: activity
  • Sun: corona
  • Sun: magnetic fields
  • Sun: photosphere

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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