Scientists observed that supergranulation cells, comprised of hot plasma roughly two to three times the diameter of Earth, form a network that drifts poleward as rapidly as comparable features at lower latitudes - ranging between 10 and 20 meters per second. This challenges earlier inferences drawn from equatorial observations, which reported slower polar drift. The findings offer insight into the ongoing plasma and magnetic field circulation that underpins the Sun's eleven-year activity cycle.
Sami Solanki, MPS Director and co-author, stated: "To understand the Sun's magnetic cycle, we still lack knowledge of what happens at the Sun's poles. Solar Orbiter can now provide this missing piece of the puzzle."
Lead author Lakshmi Pradeep Chitta commented: "The supergranules at the poles act as a kind of tracer. They make the polar component of the Sun's global, eleven-year circulation visible for the first time."
Researchers found that the magnetic network on the solar surface leaves measurable imprints in the overlying chromosphere. Images from Solar Orbiter's Extreme Ultraviolet Imager show these imprints as bright spots. By constructing a composite from eight days of observation in March, the tracks of these bright spots, seen as elongated arcs due to the Sun's rotation, were visually mapped at the south pole.
The update advises that additional data are necessary to assess whether the Sun's so-called magnetic conveyor belt remains fast near the poles over the full solar cycle. The new evidence represents a snapshot, not a continuous record, and future Solar Orbiter observations are expected to clarify these dynamics.
Research Report:Supergranulation and Poleward Migration of the Magnetic Field at High Latitudes of the Sun
Related Links
Max Planck Institute for Solar System Research
Solar Science News at SpaceDaily
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