Sun’s sluggish “Jet Stream” may have caused delay in increased solar activity

June 20th, 2009 - 12:24 pm ICT by ANI  

National Geographic Washington, June 20 (ANI): A team of astronomers has suggested that a sluggish, jet stream-like flow deep inside the sun could be to blame for the delay in increased solar activity.

The team was team led by Frank Hill of the National Solar Observatory in Tucson, Arizona, US.

According to a report in National Geographic News, the jet stream, which is actually a plasma current called a torsional oscillation, has been migrating more slowly than usual through the star’s interior.

Every 11 years, the sun generates new jet streams near its poles. These streams slowly shift from east to west toward the solar equator over a period of 17 years.

When the stream reaches a certain latitude, the sun starts producing new sunspots-relatively cool, dark regions on the sun that mark areas of magnetic disturbance.

“But the stream associated with the current cycle of solar activity has been moving even slower than normal,” Hill said.

Based on new data from sun-tracking instruments known as the Global Oscillation Network Group (GONG) and the Solar and Heliospheric Observatory (SOHO), Hill and colleagues saw that it took an extra year for the stream to cross a distance of 10 degrees latitude, compared with previous solar cycles.

The new measurements also show that the stream has finally reached the critical latitude linked to sunspot production, which could explain why solar activity finally seems to be picking up.

“It’s not clear whether this (slower jet stream) is a cause or a consequence of the mysterious solar quiet,” Hill said.

“But the fact that we see it a couple of years in advance (of the sun’s extended quiet) makes me think it’s a cause,” he added. (ANI)

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