Japan’s Arase spacecraft (formerly ERG) observed chorus waves and scattered electrons in the magnetosphere of the Earth, the origin of the pulsation auroras. The scattered electrons precipitated into the atmosphere, resulting in the aurora lights.
The origin of the intense flickering of the light high in the atmosphere of the Earth are now revealed after a decades-long yacht, a new study found.
Similar auroras can take place high above Jupiter and Saturn, according to the scientists behind the new research.
The dramatic light shows known as the northern and southern lights, also called auroras, are just as varied in nature as the colors that they show in the sky. The most famous type, known as discrete auroras, are known to be colourful ribbons and garlands of color. In contrast, pulsating auroras are giant flashing patches of light. [Aurora Guide: How the northern lights Work (Infographic)]
Auroras result when the flow of high-speed particles from the sun — collectively known as the solar wind slam into earth’s magnetosphere, the shell of electrically charged particles by the planet’s magnetic field. While discrete auroras originate a few thousand kilometers above the earth’s surface, pulsating auroras occur about 10 times further away.
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Aurora Guide: How the northern lights Work (Infographic)
Previous research has suggested that the pulsating auroras were caused by electromagnetic oscillations known as chorus waves generated in the magnetosphere on the equator. The idea was that chorus waves send electrons in the magnetosphere of the earth along the planet’s magnetic lines of force to the upper echelons of the Earth’s atmosphere, generating light, when they collide with the molecules of the air.
However, for decades, scientists could not gather sensitive enough on the ground and in the space of observations to line up on the right time and place to prove that this model. Now, researchers have finally gathered direct evidence of the chain of events behind pulsating auroras.
The scientists analyzed data of the Arase spacecraft, which was launched by the Japan Aerospace Exploration Agency at the end of 2016. This satellite can detect chorus waves and to investigate their effects on magnetospheric electrons, in a narrow window around a magnetic field line.
The researchers have also determined where the magnetic field line, the Arase spacecraft examined contact with the Earth. They searched for a pulsating aurora ‘ s matching activity of the electrons caused by chorus waves.
The scientists identified an aurora in 2017 in the heart of Canada, that was apparently generated by magnetospheric electrons scattered by chorus waves.
“Observational results are usually very complex, and the testing of theoretical predictions that often lead to ambiguous results, and that was not the case here,” said study lead author Satoshi Kasahara, a space and planetary physicist at the University of Tokyo.
The researchers noted that a similar activity may occur in the auroras of Jupiter and Saturn, where earlier work detected chorus waves. “Apply to other planets would be exciting,” said Kasahara Space.com.
The researchers detailed their findings online today (Nov. 14) in the journal Nature.
Original article on Space.com.