Scientists at the University of Iowa in the United States have finally solved the mystery of the aurora borealis, proving that a major role played by powerful electromagnetic waves during geomagnetic storms.
According to the hypothesis, the Alvenova waves, which are electromagnetic waves in the plasma that propagate along magnetic field lines, act as a particle gas pedal. Electrons in the solar wind, moving at 72 million kilometers per hour, enter the Earth’s magnetic field, are accelerated along the field lines, and enter the upper atmosphere, where they collide with oxygen and nitrogen molecules, which, in turn, go into an excited state and emit light.
This hypothesis is partially supported by data from spacecraft, which have observed Alven waves over the auroras. The final proof came from the Large Plasma Device (LPD) at the University of California, Los Angeles’ Laboratory for Basic Plasma Research. Using numerical simulations, the researchers demonstrated that the results of the experiment confirm Landau attenuation, when the energy of an electromagnetic wave is absorbed by slower-moving electrons.
According to the authors of the paper, the experiment is the first direct evidence that Alven waves can produce accelerated electrons, causing polar lights.