Scientists Stumped By Sun's Asymmetrically Reversing Magnetic Field

Carl Franzen
Talking Points Memo
Thu, 26 Apr 2012 09:11 CDT

© NOAA/NASA
The Sun's magnetic field is reversing, South becoming North, as it does approximately every 11 years on a cycle, but this time, something even stranger is going on: The North is moving much faster than the South, and space scientists aren't sure why.

"Right now, there's an imbalance between the north and the south poles," Jonathan Cirtain, NASA's project scientist for a Japanese solar mission called Hinode, in a recent article on NASA's website. "The north is already in transition, well ahead of the south pole, and we don't understand why."

Further, the asymmetrically reversing solar magnetic field could have an effect on Earth, resulting in increased solar flares and the accompanying bursts of radioactive particles called "coronal mass ejections," or CMEs, that can hit Earth and cause brilliant Northern Lights displays and problematic geomagnetic solar storms, according to NASA scientists.

"This usually leads to a double peak in the sunspot number and CME rate as a function of time," Nat Gopalswamy, a solar scientist NASA's Goddard Space Flight Center in Greenbelt, Md., in an email to TPM.

Gopalswamy and his team studied the Sun's shifting magnetic field from microwave signatures obtained by Japanese radio telescopes and reported their findings in a paper in the Astrophysical Journal on April 9.

Gopalswamy explained that while the Sun's shifting magnetic poles were first discovered in 1955, the rate at which the North and South wasn't found to be mismatched until the last few solar cycles.

To be clear, the magnetic field doesn't just flip, but rather, the Sun essentially sheds its current magnetic field and regrows a new one every 11 years. Currently, the Northern portion of the Sun is further along on this process than its Southern counterpart.

Further, the Sun's oddly shifting magnetic field affects the Solar System, though it isn't yet known just how.

"Whether the north pole of the Sun has north or south polarity decides the entry point of galactic cosmic rays into the heliosphere," Gopalswamy told TPM.

The heliosphere is an enormous magnetic bubble made up of the continual regular ejection of charged particles from the Sun. It stretches beyond Pluto.

http://www.sott.net/articles/show/244654-Scientists-Stumped-By-Sun-s-Asymmetrically-Reversing-Magnetic-Field