Two European satellite flew simultaneously above the same aurora display, and were able to take measurements at different altitudes of this natural particle accelerator.
This is the first time that scientists have measured such a region simultaneously using more than one satellite. The readings allow the electrical landscape of the acceleration region to be mapped.
“This is like geography, only instead of the contours being the height of a landscape, they are the electrical potentials that span the region,” says Göran Marklund from the Royal Institute of Technology, Stockholm, Sweden.
These electrical potentials act in both uphill and downhill directions, accelerating particles towards and away from Earth, according to their charges.