Theory Could Explain Longer Solar Cycles

BOULDER, Colo., Aug. 12 (UPI) — The sun’s cycles of sunspots, solar flares and magnetic activity may be influenced by a plasma “conveyor belt” moving across its surface, U.S. scientists say.

The sun goes through a cycle of such activities lasting around 11 years, and the level of the activity can affect navigation and communications systems on Earth, an article in the journal Geophysical Research Letters says.


But the last cycle, ending in 2008, lasted significantly longer than previous cycles, scientists say.

A study conducted by the National Center for Atmospheric Research suggests one reason for the long cycle could be changes in the sun’s conveyor belt.

In the same way Earth’s global ocean circulation transports water and heat around the planet, the sun has a conveyor belt that carries plasma along the surface toward the poles, sinks and returns toward the equator, transporting magnetic flux along the way.

Recent measurements of the longer solar cycle found the flow extended all the way to the poles, while in previous solar cycles the flow turned back toward the equator at about 60 degrees latitude.

“The key for explaining the long duration of cycle 23 with our dynamo model is the observation of an unusually long conveyor belt during this cycle,” Mausumi Dikpati of NCAR’s High Altitude Observatory says.

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Categorized | Other, Solar
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