To come to their conclusions, the physicists put to the test a 40-year-old hypothesis that electrons surf Alfven waves. They did this by creating a simulation in UCLA’s Large Plasma Device, which is essentially 20 meter-long tunnel full of sensors.
The physicists found that streams of charged particles hitch a ride on Alfven waves, illustrated here by the yellow dots. The waves then travel along the magnetic fields in Earth’s atmosphere.
Electrons (yellow balls) accelerate toward the Earth along the magnetic field lines. Alfven waves follow (blue lines) and collide with errant atoms and molecules in the atmosphere (white balls).