Solar Research: Question #6

In 1973 the United States launched its first space station, Skylab. Skylab was in the Earth’s orbit for about six years (from 1973-1979) and was equipped with x-ray telescopes to reveal the structure of the sun, specifically the corona of the sun. These x-ray images taken from both the Skylab and other satellites revealed the sun to have darker, colder spots on its corona that can be as large as the earth’s diameter and have plasma with lower density than average. We have since learned that coronal holes occur when the magnetic field of the sun is open to interplanetary space and there are regions on the sun where solar magnetic fields loop back to the sun forming arches which are depicted on x-rays as brighter areas than the rest of the corona.
            We should care about coronal holes because open configuration of the magnetic field allow particles to escape into space and research has found that coronal holes are the source of high speed solar wind streams which, when coming in contact with the Earth, can cause geomagnetic storms. Periods of high amounts of solar activity eject mass from the coronal holes and periods of low solar activity geomagnetic storms are created. From our perspective, it is important to monitor solar activity in and from coronal holes because these holes can last for several months and following them gives us the ability to predict geomagnetic disturbances

Image: http://sprg.ssl.berkeley.edu/~hhudson/drafts/sw10/sch.pdf

Darling, David. "Coronal Hole." The Worlds of David Darling. 1999. Web. 21 Oct. 2010. <http://www.daviddarling.info/encyclopedia/C/coronal_hole.html>.