(CNN) – The Northern Lights could perfectly be described as the greatest light show on Earth. This phenomenon, unique to the highest latitudes, has amazed and amazed scientists for centuries.
Experts have theorized about the causes of the Northern Lights but had never been able to prove them – until now.
Finally the great mystery of the dawn is solved
A group of physicists from Iowa State University finally showed that “the brightest auroras are produced by powerful electromagnetic waves during geomagnetic storms.” according to a recently published study.
The study shows that these phenomena, also known as Alfvén waves, accelerate electrons towards Earth, causing the particles to produce the light show we know as the Northern Lights.
“The measurements revealed that this small population of electrons has a ‘resonant acceleration’ by the electric field of the Alfvén wave, similar to a surfer catching a wave and continuing to accelerate as it moves along with the wave,” said Greg Howes, an associate professor in the Department of Physics and Astronomy at the University of Iowa and a co-author of the study.
This theory of electrons “surfing” in the electric field was first proposed in 1946 by a Russian physicist, Lev Landau, and was called the Landau Damping. His theory was now proven.
They manage to recreate the Northern Lights
For decades scientists have understood how the aurora is most likely to be created, but now for the first time they have been able to simulate it in a laboratory at the Large Plasma Device located at UCLA’s Plasma Basic Science Facility.
The scientists used a 20-meter-long camera to recreate Earth’s magnetic field using the magnetic field coils in the UCLA device. Inside the chamber, the scientists generated a plasma similar to that which exists in space near Earth.
“Using a specially designed antenna, we threw Alfvén waves down the machine, as if we were shaking a garden hose up and down quickly and watching the wave travel along the hose,” Howes said. When they began to see electrons “surfing” along the wave, they used another specialized instrument to measure how those electrons derived energy from the wave.
Although the experiment did not recreate the colorful glow we see in the sky, “our measurements in the laboratory clearly matched predictions from computer simulations and mathematical calculations, showing that electrons surfing in Alfvén waves can accelerate electrons ( up to speeds of over 72 million km / h) causing the aurora, “Howes said.
“These experiments allow us to make the key measurements that show that spatial measurements and theory, in fact, explain an important way that auroras are created,” said study co-author Craig Kletzing.
This finding may help to better understand the climate in space.
Space scientists across the country were elated at the news. «I was tremendously excited! It’s very rare to see a laboratory experiment that validates a theory or model about the space environment, “said Patrick Koehn, a scientist in NASA’s Heliophysics Division. “The space is too large to be easily simulated in the laboratory,” he explained.
Koehn believes that being able to understand the acceleration mechanism of electrons that cause auroras will be useful in many studies in the future.
“It helps us better understand the climate in space. The electron acceleration mechanism verified by this project works in other parts of the solar system, so it will find many applications in space physics. It will also be useful in predicting space weather, something NASA is very interested in, “Koehn said in an email to CNN.
There is a long way to go
Now that the theory of how the aurora is created has been proven, there is still a long way to go to forecast how strong each storm will be.
“Predicting how strong a particular geomagnetic storm will be based on observations of the Sun and spacecraft measurements between Earth and the Sun remains an unsolved challenge,” Howes said in an email.
“We have established the bond of electrons surfing in Alfvén waves about 16,000 km above the Earth’s surface, and now we must learn to predict the strength of those Alfvén waves using observations from spacecraft,” he added.