Scientists have observed the cause of the Northern Lights for the very first time. According to them, the shower of electrons bouncing across the Earth’s magnetic field cause the Aurora Borealis, the colourful phenomenon which is commonly known as the Northern Lights.
The phenomenon of the lights has always been hypothesized as the researchers have never directly observed the underlying mechanism until now.
Scientists, with the onset of a new satellite with advanced measuring tools, have identified that this wonderful phenomenon is caused by the interaction between electrons and plasma waves.
This interaction takes place in the Earth’s magnetosphere, the region in which the behaviour of the electric particles is governed by the planet’s magnetic field.
Satoshi Kasahara, Associate Professor at the University of Tokyo in Japan, said, “Auroral sub storms are caused by global reconfiguration in the magnetosphere, which releases stored solar wind energy.”
Kasahara, who is also the lead author of the study which is published in the journal Nature, also said, “They are characterized by auroral brightening from dusk to midnight, followed by violent motions of distinct auroral arcs that eventually break up, and emerge as diffuse, pulsating auroral patches at dawn.”
The phenomenon happens when a specific type of plasma waves, called the chorus waves, rain electrons in the upper atmosphere. This stabilizes the system and gives off a colourful light as the electrons fall.
However, a question is still raised by the scientists as if the chorus waves are powerful enough to excite the electrons to the extent of creating the auroras.
Kasahara said, “We, for the first time, directly observed scattering of electrons by chorus waves generating particle precipitation into the Earth’s atmosphere. The precipitating electron flux was sufficiently intense to generate pulsating aurora.”
Since typical electron sensors could not distinguish the precipitating electrons from others, the scientists could not observe this evidence before. Researchers designed a specialised electron sensor which observed the accurate interactions of the auroral electrons driven by chorus waves.
The specialised sensor was aboard the Exploration of energisation and Radiation in Geospace (ERG) satellite, also known as the Arase spacecraft, launched by the Japan Aerospace Exploration Agency.
Kasahara said, “By analyzing data collected by the ERG spacecraft more comprehensively, we will reveal the variability and further details of plasma physics and resulting atmospheric phenomena, such as auroras.”