News – The Sun’s hot outer layer, the corona, has a very different chemical shape from the colder inner layers, but the reason for this has been a concern for scientists. for decades.
One explanation is that, in the middle layer (the chromosphere), magnetic waves exert a force that separates the sun’s plasma into different parts, so that only the ion grains are carried in. to the corona, while leaving neutral particles behind (thus leading to its buildup of elements such as iron, silicon and magnesium in the outer atmosphere).
Now, in a new study published in The Astrophysical Journal, researchers combined observations from a telescope in New Mexico, USA, with satellites near Earth to identify a connection between magnetic waves in the chromosphere and areas of abundant ionized particles in the hot outer atmosphere.
Lead author Dr Deborah Baker (UCL Space & Climate Physics) said: “The various chemical compounds of the inner and outer layers of the sun were first observed more than 50 years ago. one of the long-standing open-ended questions in astronomy.
“The difference in combination is surprising, as the layers are physically connected, and that subject in the corona comes from the innermost layer, the photosphere.
“Now, thanks to a unique combination of ground-based and space-based studies of the solar atmosphere, carried out almost simultaneously, it was possible to detect magnetic waves in the chromosphere and connect them with an abundance of elements in the corona not found in the inner regions of the sun.
“It is vital to identify the processes that shape the corona as we seek to gain a better understanding of the solar wind, a stream of loaded grains emanating from the Sun, which can destroy and damage to satellites and infrastructure on Earth.
“Our new findings will help us study the sun’s wind and trace it back to where it comes from in the solar atmosphere.”
The findings build on the results of a related paper by many of the same authors, published last month in the Philosophical Activities of the Royal Society, which found unparalleled magnetic waves in the chromosphere, regulates other factors that may have created similar magnetic oscillations.
The existence of magnetic waves – vibrations of ions traveling in a specific direction – was first theorized in 1942 and is thought to have been created by millions of nanoflares, or micro-explosions, including place in the corona every second.
The research team behind the new paper found the direction of the waves by shaping a range of magnetic fields and found that waves appearing in the chromosphere appeared to be magnetically connected to areas of ionized grains in the corona.
Dr Marco Stangalini (Italian Space Agency and National Institute of Astrophysics, Rome), who co-authored the two papers, said: “The difference in chemical fusion between the interior, the photosphere, with the corona being a feature not only of our own sun, but of stars around the Earth, so by keeping an eye on our local laboratory, the Sun, we can develop an understanding of the Universe far beyond. “
Both papers used observations obtained by IBIS, the high-resolution spectropolarimetric imaging at the Dunn Solar Telescope in New Mexico, along with images from the EUV (EIS) imaging spectrometer on the Japan / UK / US Hinode Solar Observatory (EIS). a device designed and built by a UCL-led team) and data from NASA’s Solar Dynamics Observatory (SDO).
The researchers say their findings provide a basis for future research using data from the Solar Orbiter, the mission of the European Space Agency that receives close-up images of the Sun. The mission, launched in February last year, includes instruments proposed, designed and built at UCL.
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