American space physicists have released unprecedented details on a bizarre phenomenon that powers the northern lights, solar flares and coronal mass ejections, the biggest explosions in the solar system.
Magnetic reconnection can be loosely defined as the merger of magnetic fields that releases an astonishing amount of energy. It remains mysterious, especially since it breaks the standard law governing charged particles, or plasma, according to the study, published Tuesday in Physical Review Letters.
Jan Egedal, a professor of physics and the paper's senior author, and his colleagues at University of Wisconsin-Madison studied recordings from Oct. 15, 2016, when the Magnetosphere Multi-scale satellite passed through the point where the solar wind meets Earth's magnetic field.
"Our data clearly show that electrons suddenly cease to follow magnetic fields and zoom off in another direction, corkscrewing and turning. That begs for explanation," Egedal said.
The activity confirmed the theoretical descriptions of magnetic reconnection. But it has violated the standard law governing the behavior of plasmas, clouds of charged particles that comprise, for example, the solar wind.
"The 'plasma frozen-in law' says electrons and magnetic fields have to move together always, and suddenly that does not apply here," Egedal said.
By now, magnetic reconnection has been known to be linked to black holes, pulsars, supernovas and active galactic nuclei.
"When one of these fantastic space telescopes sees a massive burst of X-rays that lasts just tens of milliseconds coming from an object in a galaxy far away, this giant burst of energy at such a great distance may reflect a massive reconnection event," said Cary Forest, also a professor of physics at the university.
"If we understand reconnection better, perhaps we can improve space weather forecasts," Egedal said. "We can look at the sun to predict what may happen in two to four days, which is how long the wind from the sun takes to reach Earth."
