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Eruptions of plasma from the sun's surface during a solar storm. (SDO)
Images from NASA’s Solar Dynamic Observatory (SDO) spacecraft have shown that solar storms are caused by a rapid phenomenon known as a magnetic rope.
Associate professor Jie Zhang and graduate student Xin Cheng at George Mason University looked at images taken with SDO’s Atmospheric Imaging Assembly (AIA) telescope, which captures imagery every 10 seconds. They zoomed in on a solar region where a magnetic rope was forming.
"The magnetic rope triggers a solar eruption,” said Zhang in a press release. “Scientists have been debating whether or not this magnetic rope exists before a solar eruption. I believe that the result of this excellent observation helps finally solve this controversial issue.”
During a solar storm, the sun sends out giant clouds of plasma with a strong magnetic field. The telescope showed that a long, low channel courses through the active region beforehand, slowly rising as it heats up to as much as 10 million degrees. This channel is believed to be the magnetic rope.
Normally, the sun’s magnetic field lines take the form of semi-circles looping out from the surface. These do not tend to erupt, instead they often having the opposite effect of inhibiting eruptions.
Close-up shots of one of the eruptions. (SDO)
However, a rope forms when multiple lines of a magnetic field wrap together along a central axis, generating a powerful electric current with the potential to send the rope outward.
"Understanding the eruption process of these storms will definitely help us better predict them," Zhang said. "We cannot prevent solar storms, just like we cannot prevent earthquakes or volcanoes.”
“But the development of prediction capacity can help mitigate adverse effects. For instance, satellite operators can power-down key systems to prevent the possible damage to the systems."
