A new form of auroras

a Few Amateurs from Finland captured a new form of auroras, which scientists are unable to attribute to any of the existing categories.

Unusual glow called “dunes”. Recently, experts have found an explanation of how is this phenomenon and how it is related to the activity of the Sun and the flow of ions in the Earth’s atmosphere.

the auroras are the result of the interaction between the solar wind and the Earth’s atmosphere. Charged particles emitted by the Sun affect the atoms in the Earth’s ionosphere. Because of this, the atoms emit light.

typically, the radiance becomes one of three forms: arcs, bands, or pillars. Sometimes it is observed in the form of a crown. However, the phenomenon depicted in 2018, did not fall under any of the conventional categories.

those pictures drew the attention of the Professor of the University of Helsinki Minna Palmroth (Minna Palmroth). In 2018, the woman worked on his book, which was written for people watching the Aurora. It had collected thousands of images of this natural phenomenon made by Amateur photographers with whom she spoke in the thematic community on “Facebook”.

dealing with the classification of images, Palmroth noticed that the shape of some patterns of the Aurora does not fit into existing categories. The researcher has postponed these shots to deal with them later.

After the publication of the Professor continued to send a picture all the same shape glow. A group of scientists described it as “greenish and smooth undulating pattern, reminiscent of the layered clouds or the dunes on a sandy beach”.

interestingly, this phenomenon was captured in one and the same time in two places in Finland, and both images were observed the same patterns of the Aurora. One of the authors of the subsequent studies Maxim Grandin (Grandin Maxime) has identified the coordinates of stars that were also visible on the submitted images. He was helped in this astronomical softwareMMA Stellarium. The calculations allowed to use the lights as points of reference in determining the height and extent of auroras.

it Turned out that all the “dunes” were formed at a relatively low altitude: about 100 kilometers, that is in the upper part of the mesosphere.

In recognition of Palmroth, these heights are extremely difficult to study with satellites. For this reason, the strip is from 80 to 120 kilometers above the Earth scientists themselves often referred to as “ignorosphere”. And it was there that he discovered “dune”.

All this led the scientists actually create new scientific methods at the interface of atmospheric and space research.

Experts began to track the conditions that accompany the emergence of the “dunes” in the sky. In the end, they came to the conclusion that the different brightness of the lights inside “dune” is determined either by the waves of particles that come from outer space, or variations in the density of oxygen atoms that fall under this bombardment.

Finnish experts have identified as the density of oxygen atoms is influenced by waves of different lengths, travelling in the atmosphere in different directions.

Scientific article on the study was published in the journal of the AGU Advances.

By the way, the authors of the project “Nestinarka” told about the other kind of lights discovered by Amateurs. We also wrote about why the auroras of the Earth are different in the North and the South. We talked about another unusual natural phenomenon – “the glow of hundreds of moons”.

Text: To.Science