Since the dawn of time, humans have been mystified by what causes the aurora borealis or northern lights. However, a group of scientists has finally uncovered what causes the dazzling light show that has captivated people for so long.
Researchers at the University of Iowa have proven that the shimmering auroras are the result of powerful electromagnetic waves during geomagnetic storms, according to a newly published study.
According to the study, phenomena known as Alfven waves propel electrons toward Earth and cause the particles to produce the brilliant display of northern lights seen in the higher latitudes of our planet,
“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,” Prof. Greg Howes, a co-author of the study, told CNN.
Scientists have long understood that the aurora was the likely result of electrons surfing across the electric field, at least since the theory was introduced in 1946 by Soviet scientist Lev Landau.
However, the University of Iowa professors were able to finally put the theory to the test through a simulation at a lab at the Large Plasma Device (LPD) in the Basic Plasma Science Facility of the University of California, Los Angeles (UCLA).
Using a 20-meter-long chamber to simulate the magnetic field of the Earth through state-of-the-art magnetic field coils, scientists were able to generate plasma similar to that which exists in space.
“Using a specially designed antenna, we launched Alfven waves down the machine, much like shaking a garden hose up and down quickly, and watching the wave travel along with the hose,” said Howes.
While this didn’t result in the type of auroras we might see in the sky, “our measurements in the laboratory clearly agreed with predictions from computer simulations and mathematical calculations, proving that electrons surfing on Alfven waves can accelerate the electrons (up to speeds of 45 million mph) that cause the aurora,” Howes noted.
Scientists across the country were elated by the results of the experiment.
“I was tremendously excited! It is a very rare thing to see a laboratory experiment that validates a theory or model concerning the space environment,” said Patrick Koehn, a scientist in the Heliophysics Division of NASA.
“Space is simply too big to easily simulate in the lab,” he added.
Researchers are hopeful that a greater understanding will allow forecasters to better understand weather conditions in space.