“If the plasma that makes up the sun were completely static, we know that the sun's magnetic field would decay over time, and pretty soon, there would be no sunspots or other solar activity. However, the plasma in the sun is moving, and that motion is able to regenerate and maintain the sun's magnetic field,” said Daniel Leconte, a theoretical physicist at Northwestern University in Illinois and a co-author of the study.
The solar magnetic field fluctuates in a specific pattern, with sunspots — regions with very large magnetic fields — emerging and then disappearing every 11 years, making the Sun, as Vasil put it, “a giant magnetic clock.”
“But we don't yet know the full story about how this happens. Complex interacting fluid motions (in this case, solar plasma) ultimately drive the dynamo, but we can't yet explain the details,” Vasil said.
The Italian polymath Galileo made the first detailed observations of sunspots using telescopes he invented in 1612. In the early 20th century, American astronomer George Hale determined that sunspots are magnetic.