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upstart writes:

Physicists determine how auroras are created:

[...] In a new study, a team of physicists led by University of Iowa reports definitive evidence that the most brilliant auroras are produced by powerful electromagnetic waves during geomagnetic storms. The phenomena, known as Alfven waves, accelerate electrons toward Earth, causing the particles to produce the familiar atmospheric light show.

The study, published online June 7 in the journal Nature Communications, concludes a decades-long quest to demonstrate experimentally the physical mechanisms for the acceleration of electrons by Alfven waves under conditions corresponding to Earth's auroral magnetosphere.

"Measurements revealed this small population of electrons undergoes 'resonant acceleration' by the Alfven wave's electric field, similar to a surfer catching a wave and being continually accelerated as the surfer moves along with the wave," says Greg Howes, associate professor in the Department of Physics and Astronomy at Iowa and study co-author.

Journal Reference:
J. W. R. Schroeder, G. G. Howes, C. A. Kletzing, et al. Laboratory measurements of the physics of auroral electron acceleration by Alfvén waves [open], Nature Communications (DOI: 10.1038/s41467-021-23377-5)

Also at Nature

Original Submission