Solar corona is the outer part of our star atmosphere. It can be successfully observed during a few total eclipses. Then our Moon covers the entire solar disk and the corona in the form of a bright halo becomes visible for viewing. The whole atmosphere of the star is very heterogeneous, this also applies to the corona. In the structure of the crown there are holes, protuberances and loops. Their size, configuration and structure is constantly changing throughout the cycles of solar activity. Below is a diagram of the structure of the Sun with layers.
Solar Corona, Radiation Lines
Early studies of scientists and astronomers who like the solar spectrum revealed many different lines and radiations that were difficult to compare with something. Known chemical elements did not produce such lines during spectral analysis. Some have expressed the opinion that there are substances unknown to the earth science that are present in the star. The substance has received its name – the colorna.
Element tried to open until they paid attention to the temperature of the solar corona. Its value exceeded 1 million degrees Celsius. This temperature causes the complete ionization of the substances in the atmosphere: hydrogen and helium. They lose their electrons and cannot radiate in the usual spectrum. Therefore, against the background of ionization, the visible part of the radiation becomes characteristic of rare elements unusual for the main composition of the star. The lines of ionized iron and calcium begin to stand out. The combination of their spectra and gave an unknown coronium, which led to the frenzy of scientists.
Now, to observe the Solar corona, it is not necessary to wait long for the next total eclipse. There are new tools for the study of the corona (coronagraphs), which at any time close the solar disk with special valves and provide an opportunity to study the atmosphere of our star. In addition, on our website you can find a lot of photos of the solar corona in various filters.
X-ray solar corona
Studies of the solar corona from the earth in the visible range are the exception today. All the study scientists moved into the X-ray range, invisible from the surface of the Earth. This is caused by a very high temperature on the surface of the star. In addition, the photosphere and the chromosphere of the Sun do not produce almost x-rays and do not interfere with their radiation scientists to observe and study the corona.
Optics for studying and photographing the X-ray spectrum are significantly different from the usual. You will not be able to observe the solar corona, even if you buy the most expensive telescope. The fact is that the instrument suitable for studying the corona must be located outside our earth’s atmosphere — aboard a satellite or a geophysical rocket. At the end of the last century, the Japanese satellite Yohkoh gave a lot of useful information. His study of the corona took place from 1991 to 2001. In our century, the study of the corona in the X-ray spectrum of satellites: Coronas-F, Soho and Trace. The Russian Coronas-Photon was launched into Earth orbit in 2008. On board there is a set of equipment with a Teses telescope for obtaining high-resolution photographs. They will help solve many mysteries and give answers to the nature of our luminary and its corona. Physicists have received an excellent tool for the study of the nearest star and space.
Astronomers Close to Solving the Secrets of the Solar Corona
Using data from NASA’s “Magnetospheric Multi-Scale” mission, astronomers for the first time directly “saw” the process of energy transfer in space from chaotic electromagnetic fields to particles that make up the solar wind, which will potentially help solve the secret of heating the solar corona and processes surrounded by black holes. The results of the study are presented in the journal Nature Communications.
Our work shows that a process known as Landau damping is responsible for the transfer of energy in space from electromagnetic plasma turbulence to electrons in the solar wind, which leads to the heating of interplanetary space.
-study authors
The phenomenon, named after the Soviet Nobel laureate in physics Lev Landau (1908-1968), occurs when a wave passes through a plasma and plasma particles, which, when moving at a speed slightly lower than the phase velocity of the wave, absorb its energy. Although this process has previously been observed in some simple situations, it has not yet been clear whether it works in very turbulent and complex environments that occur naturally in space, or is everything different there.
Throughout the universe, plasma matter is heated to much higher temperatures than expected. For example, the solar corona is hundreds of times hotter than the surface of the sun, and this mystery remains to be revealed. It is also important to understand the heating of many other astrophysical plasmas, such as the interstellar medium and plasma disks surrounding black holes, in order to explain some of the extremes occurring there.
Plasma is the most common form of visible matter in the Universe and is often in a very dynamic and seemingly chaotic state known as turbulence. In their work, using the high-resolution data collected by the Magnetospheric Multi-Scale probes, as well as the recently developed method for analyzing the correlation of fields and particles, scientists were able to evaluate turbulent heating in natural astrophysical plasma for the first time. In addition, they tested a new approach to analysis as a tool that can be used to probe plasma energy and in a number of other studies on various aspects of its behavior.
We have shown that in the Landau damping process, an electric field associated with waves moving through a plasma can accelerate electrons rushing at the correct speed. This first successful application of the new method demonstrates its ability to respond to long-standing, fundamental questions about the behavior and evolution of cosmic plasma, such as heating the solar corona.
-Greg House, co-author of the study at the University of Iowa (USA)
The results, as scientists note, pave the way for the use of the new method in future and current missions, such as NASA’s Parker Solar Probe, which is the first to explore the solar corona and plasma environment near the Sun.
Solar Corona, revealing the secrets
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