NASA Captures Never-Before-Seen Magnetic Explosion on Surface of the Sun
NASA scientists have observed a new type of magnetic explosion in the outermost layer of our sun's atmosphere, known as the corona.
The explosion, known as forced magnetic reconnection, is triggered by an eruption on the sun that causes tangled magnetic field lines to snap and realign, shooting out particles and energy.
Previously scientists had only ever witnessed spontaneous magnetic reconnection, which is not necessarily linked to eruptions on the sun. But observations from NASA's Solar Dynamics Observatory (SDO) revealed, for the first time in the solar corona, a forced reconnection event triggered by one of these eruptions.
The event was clearly visible when scientists looked at SDO observations of plasma—one of the four fundamental states of matter consisting of superheated, charged particles.
The SDO data revealed a prominence—a large loop of plasma—moving up from the visible surface of the sun, known as the photosphere. In a series of images taken over an hour, the prominence can be seen falling back into the photosphere.
As this happens, the prominence interacts with a collection of magnetic field lines, causing them to reconnect in a distinct "X" shape. This sparked a magnetic explosion causing the prominence to gain heat, according to a study published in the Astrophysical Journal.
"This was the first observation of an external driver of magnetic reconnection," Abhishek Srivastava, one of the authors of the study from the Indian Institute of Technology (BHU), said in a statement.
"This could be very useful for understanding other systems. For example, Earth's and planetary magnetospheres, other magnetized plasma sources, including experiments at laboratory scales where plasma is highly diffusive and very hard to control," he said.
The latest observations confirm a theory that was proposed around 15 years ago. According to the authors, the results could have significant implications for space weather prediction, particle physics experiments on Earth and our understanding of the sun's atmosphere.
For example, magnetic reconnection could explain one of the great mysteries of solar science—the fact that the corona is millions of degrees hotter than the lower layers of the sun's atmosphere. The prominence gained heat during the forced reconnection event, which could be one possible mechanism through which the corona is heated locally.
The next step for the scientists is to detect more forced reconnection events, which will provide further insights into this phenomenon.
"Our thought is that forced reconnection is everywhere," Srivastava said. "But we have to continue to observe it, to quantify it, if we want prove that."
