Computer Models Reveal Solar Polar Vortices for First Time

In the simulations, a tight ring of polar vortices forms at around 55 degrees latitude, the equivalent of Earth’s Arctic circle. After forming, the vortices head toward the poles in a tightening ring, shedding vortices as the circle closes, eventually leaving only a pair of vortices directly abutting the poles before they disappear altogether at solar maximum. How many vortices form and their configuration as they move toward the poles changes with the strength of the solar cycle.

Summary: Scientists have used advanced computer simulations to predict the existence of swirling vortices at the Sun’s poles, similar to those found on Earth and other planets. The research suggests these solar vortices form distinctive patterns that change with the Sun’s magnetic cycle, potentially offering new insights into solar behavior.

Journal: Proceedings of the National Academy of Sciences, November 11, 2024, DOI: 10.1073/pnas.2403816121 | Reading time: 4 minutes

A Solar Mystery Unveiled

While we’ve observed polar vortices on Earth, Jupiter, Saturn, and other planets in our solar system, the Sun’s poles have remained a mystery. “No one can say for certain what is happening at the solar poles,” explains NSF NCAR senior scientist Mausumi Dikpati, who led the new study.

Unlike planets, where we can directly observe polar regions, humanity has never sent a mission capable of viewing the Sun’s poles. This limitation has left scientists relying on computer models to understand what might be happening in these crucial areas.

A Dance of Magnetic Forces

The research reveals a unique pattern of vortex formation. These swirling structures first appear at about 55 degrees latitude – equivalent to Earth’s Arctic Circle. They then move toward the poles in a tightening ring, gradually shedding vortices until only two remain at the poles themselves.

This process is tied to the Sun’s magnetic cycle. The vortices eventually disappear completely during solar maximum, when the Sun’s magnetic field reverses polarity at the poles. The number and arrangement of vortices varies depending on the strength of the solar cycle.

Planning Future Solar Missions

The findings have important implications for future solar observation missions. “You could launch a solar mission, and it could arrive to observe the poles at completely the wrong time,” notes Scott McIntosh, a co-author of the paper.

The research suggests that polar vortices should be visible during most of the solar cycle, except at solar maximum. This timing could be crucial for planning missions like the Solar Orbiter, a joint NASA-European Space Agency project that will provide our first glimpse of the solar poles.

Glossary

  • Solar maximum: Peak of solar activity when magnetic fields reverse
  • Polar vortex: A spinning formation in fluid around a rotating body
  • Solar cycle: Regular pattern of changes in the Sun’s magnetic activity
  • Plasma: The hot, magnetized gas that makes up the Sun’s outer layers

Quiz

  1. At what latitude do the solar polar vortices first form?
    Answer: 55 degrees latitude
  2. When do the polar vortices disappear?
    Answer: At solar maximum
  3. Why haven’t we directly observed these vortices?
    Answer: No mission has been able to observe the Sun’s poles
  4. What makes the Sun’s vortices different from planetary ones?
    Answer: They are influenced by magnetic fields

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