Mysterious Electron Acceleration Explained
by David L. Chandler
A mysterious phenomenon detected by space probes has finally been explained, thanks to a massive computer simulation that was able to precisely align with details of spacecraft observations. The finding could not only solve an astrophysical puzzle, but might also lead to a better ability to predict high-energy electron streams in space that could damage satellites.
Jan Egedal, an associate professor of physics at MIT and a researcher at the Plasma Science and Fusion Center, working with MIT graduate student Ari Le and with William Daughton of the Los Alamos National Laboratory (LANL), report on this solution to the space conundrum in a paper published Feb. 26 in the journal Nature Physics.
Egedal had initially proposed a theory to explain this large-scale acceleration of electrons in Earth’s magnetotail — a vast and intense magnetic field swept outward from Earth by the solar wind — but until the new data was obtained from the computer simulation, “it used to be people said this was a crazy idea,” Egedal says. Thanks to the new data, “I don’t get that anymore,” he says.
The simulation shows that an active region in Earth’s magnetotail, where “reconnection” events take place in the magnetic field, is roughly 1,000 times larger than had been thought. This means a volume of space energized by these magnetic events is sufficient to explain the large numbers of high-speed electrons detected by a number of spacecraft missions, including the Cluster mission...
(read more: PhysOrg) (image: NASA)
