[music throughout] In the scorching upper
reaches of the Sun’s atmosphere, the corona, scientists have just seen a new type of magnetic
explosion. The explosion known as forced or
controlled magnetic reconnection, is triggered by an eruption on the Sun which causes
tangled magnetic field lines to explosively snap and realign, shooting
out particles and energy. The discovery may help
scientists understand a key mystery about how the corona, the Sun’s outermost layer,
is millions of degrees hotter than layers below it.
Previously, scientists had only seen spontaneous reconnection.
which is not necessarily linked to an eruption or external forcing on the Sun.
The forced reconnection event was clearly visible
when the scientists used observations from NASA’s Solar Dynamics Observatory
to look at a wavelength of showing plasma heated to six million degrees.
The data showed a prominence,
a large loop of plasma moving up from the visible surface of the Sun, the photosphere
In a series of images take over an hour, the
prominence could be seen falling back into the photosphere.
En route, the prominence ran into a snarl of magnetic field lines, causing them to
reconnection in a distinct X shape. The data from the event
showed that the prominence, which was fairly cool relative to the blistering corona,
gained heat from the event. The temperature of the reconnection point was also
elevated. This suggests that forced reconnection might be
one way that the corona is heated locally.
The scientists are continuing to look for more forced reconnection events.
With more observations, they can begin to understand the mechanics behind the
reconnection and how often it might happen.
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