SDO sees new kind of magnetic explosion on sun

The article also explains why ‘understanding forced reconnection can help modelers better predict when disruptive high-energy charged particles might come speeding at Earth.’

NASA’s Solar Dynamics Observatory has observed a magnetic explosion the likes of which have never been seen before, reports Phys.org.

In the scorching upper reaches of the Sun’s atmosphere, a prominence—a large loop of material launched by an eruption on the solar surface—started falling back to the surface of the Sun.

But before it could make it, the prominence ran into a snarl of magnetic field lines, sparking a magnetic explosion.

Scientists have previously seen the explosive snap and realignment of tangled magnetic field lines on the Sun—a process known as magnetic reconnection—but never one that had been triggered by a nearby eruption.

The observation, which confirms a decade-old theory, may help scientists understand a key mystery about the Sun’s atmosphere, better predict space weather, and may also lead to breakthroughs in the controlled fusion and lab plasma experiments.

“This was the first observation of an external driver of magnetic reconnection,” said Abhishek Srivastava, solar scientist at Indian Institute of Technology (BHU), in Varanasi, India. “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.”

Previously a type of magnetic reconnection known as spontaneous reconnection has been seen, both on the Sun and around Earth. But this new explosion-driven type—called forced reconnection—had never been seen directly, thought it was first theorized 15 years ago.

The new observations have just been published in the Astrophysical Journal.

The previously-observed spontaneous reconnection requires a region with just the right conditions—such as having a thin sheet of ionized gas, or plasma, that only weakly conducts electric current—in order to occur.

The new type, forced reconnection, can happen in a wider range of places, such as in plasma that has even lower resistance to conducting an electric current. However, it can only occur if there is some type of eruption to trigger it. The eruption squeezes the plasma and magnetic fields, causing them to reconnect.

Full article here.