Laboratory experiments fully confirmed theoretical calculations that linked the appearance of auroras with the acceleration of electrons by Alfvén waves in plasma.
When a stream of charged particles rushes from space to Earth, numerous electrons collide with oxygen and nitrogen ions in the upper atmosphere, coloring the sky with red and green flashes of aurora. It is believed that they are drawn into motion and directed by waves that arise in the rarefied plasma under the influence of the planet's magnetic field.
Electromagnetic waves cause charged plasma to oscillate, creating MHD Alfven waves. Having “saddled” them, like surfers, electrons rush towards the Earth - or another planet, because auroras exist in other worlds, for example, on Saturn. This mechanism has now been demonstrated in a precision laboratory experiment. Scientists write about him in a new article published in the journal Nature Communications.
Wheaton College Professor James Schroeder and his colleagues have built the Large Plasma Device (LAPD), a tube about a meter in diameter and over 16 meters long, filled with rarefied plasma. An antenna located at one end of the pipe sent electromagnetic waves along it, which caused the appearance of Alfven waves.
After tracing the flight of electrons on the LAPD, the authors confirmed that they are carried away by waves, and that they pick up speed exactly as predicted by the calculations carried out for the auroras. Scientists summarize: "Now, experiments, theory and computer simulations demonstrate a clear causal relationship between Alfven waves and electron acceleration, which directly leads to the emergence of auroras."