Coronal mass ejections (Coronal mass ejections or CME) are gigantic volumes of solar matter ejected into interplanetary space from the Sun's atmosphere into as a result of active processes occurring in it. Apparently, it is the matter of coronal ejections reaching the Earth that is the main cause of disturbances in the Earth's magnetosphere and magnetic storms. Nature emissions and the reasons why they occur are not yet fully understood. For example, it has long been known that coronal mass ejections often (perhaps always) associated with solar flares, but the mechanism of this connection has not yet been established. It is not even known whether it precedes ejection outbreak or, conversely, is its consequence.
Although observations of the distant corona of the Sun during eclipses go back thousands of years, the existence coronal mass ejections remained unknown until the beginning of the space age. The first observational evidence of this phenomenon was obtained about 35 years ago on the coronagraph of the solar orbital station OSO 7, which operated in orbit from 1971 to 1973. The reason why the opening coronal mass ejections happened so late, is that the total phase of solar eclipses lasts on Earth for a very short time (only a few minutes), which is not enough to detect coronal ejection lasting several hours. In addition, ground-based coronagraphs are unable to detect weak radiation emission due to the bright glow of the sky. Coronagraphs installed on board spacecraft are free from this drawback and, as a result, provide ample opportunities for research. coronal ejections.
Enormous coronal mass ejection, solar cycle 23.
Coronal mass ejection on May 15, 2000. LASCO 3 instrument, SOHO space solar observatory.
Solar eruptions, called coronal mass ejections (CMEs), are associated with the breaking of closed magnetic field lines above the surface of the Sun. Depending on the energy realized during the eruption, the solar wind from the CME has either high or low speeds. The frequency of CME occurrence is synchronous with the solar activity cycle. Moderate solar wind flows from coronal rays - bright, dense structures. The “quiet corona” between the holes and rays can also conduct slow flows of solar matter.
The dynamic properties of the solar wind are very closely related to the corona and its magnetic field. A significant part of the solar magnetic field, stretching, is carried away by the wind carried away from the Sun. It blows in all directions, filling the entire circumsolar space, our entire planetary system, with charged particles, creating an interplanetary magnetic field maintained by the wind.
"Railway Storm", May 13, 1921. On that day, astronomers noticed a huge sunspot with a radius of approximately 150 thousand kilometers. On May 15, a geomagnetic storm followed, which disabled half of the equipment of the New York Central Railroad and left almost the entire East Coast of the United States without communications.
Solar flares July 21, 2012. Active solar region 1520 released a huge X1.4-class flare towards Earth, causing auroras and severe disruptions in radio communications. Class X flares are the most powerful of all known in terms of X-ray intensity. They themselves usually do not reach the Earth, but their influence on the magnetic field cannot be underestimated.
The 1972 outbreak and Apollo 16. Traveling through space during maximum solar activity is extremely dangerous. In August 1972, the crew of Apollo 16 on the Moon narrowly escaped the effects of an X2 class flare. If the astronauts had been any less lucky, they would have received a radiation dose of 300 rem, which would almost certainly have killed them within a month.
Solar flare on Bastille Day. On July 14, 2000, satellites detected a powerful X5.7 class flare on the surface of the Sun. The ejection was so strong that even the Voyager 1 and 2 spacecraft, located at the edge of the solar system, detected it. There were interruptions in radio communications throughout the Earth, and people flying over the poles of the planet received a dose of radiation - fortunately, a relatively small one.
The solar flare of August 9, 2011 marked the peak of the current solar cycle, reaching a magnitude of X6.9. It was the largest of the Cycle 24 emissions detected by NASA's new Solar Dynamics Observatory satellite. The flare ionized the Earth's upper atmosphere, causing interference in radio communications.
The largest outbreak of 2015 occurred on May 7. Its power reached “only” class X2.7, but this was enough to cause bright auroras and communication interruptions. And besides, there are beautiful photographs from observing satellites.
The solar flare on December 5, 2006 reached a record power of X9, but fortunately was not directed towards the Earth. Our planet, in principle, is a rather small “target”, with which humanity is very lucky. Two STEREO solar probes recently launched into orbit tracked the event from start to finish.
The geomagnetic storm of March 13, 1989 demonstrated how dangerous solar storms can become. The impact of the X15 outbreak has caused power outages for millions of Canadians in Montreal and the surrounding Quebec area. The electrical networks of the northern United States barely withstood the electromagnetic shock. All over the world, radio communications were interrupted and the aurora was spreading.
The Halloween flare of October 2003 was one of the most powerful X45 class solar storms ever recorded. It mostly missed Earth, but the coronal mass ejections damaged a number of satellites and caused interruptions in telephone and mobile communications.
Carrington's Superstorm. On September 1, 1859, astronomer Richard Carrington observed the brightest flare, the coronal ejection from which reached the Earth in only 18 hours. Telegraph networks failed throughout Europe and the United States, and some stations caught fire due to short circuits. That ejection wasn't the largest, around X10, but it hit the Earth at the perfect time and caused the most destruction.
The power of “solar storms” reaches billions of megatons of TNT—that’s how much energy our entire civilization could consume in a million years. Coronal mass ejections are mainly represented by electromagnetic radiation, which, when accurately hitting the Earth, causes geomagnetic storms. The consequences are interruptions in communication and failure of electronics. Considering that every year humanity relies more and more on technology, a strong geomagnetic storm can cause real chaos. Here are the 10 most powerful solar storms of the last two centuries.
Solar flares
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Data from the SPIRIT experiment (FIAN) - on the CORONAS-F satellite - Flash 10/28/03, 11:00 UT X17.2/4B, S16E08 – UV (MgXII line - 8.42 A). |
A solar flare is a powerful manifestation of SA caused by the emergence of an unstable magnetic field configuration in an active region on the Sun. Flares are observed in the form of a sudden increase in the brightness of the solar chromosphere, and during powerful events, the photosphere. The flare lasts from several minutes to tens of minutes and is accompanied by the release of energy up to 10 26 J in the form of a coronal ejection of mass and a flux of cosmic rays, electromagnetic radiation in all ranges from ultraviolet, x-ray and gamma radiation to meter radio waves. |
What determines the degree of geoeffectiveness of solar flares?
Not every flare that occurs on the Sun affects the state of the NEC, that is, it is geoeffective. The geoeffectiveness of flare events is mainly determined by power (intensity) and localization on the solar disk. Naturally, the more powerful the flare, the more powerful the impact it can have on the NEO, provided that the particles formed in it reach the Earth’s orbit. According to recent studies, X-ray flares above M5 that occur on the western half of the solar disk (for example,) have maximum geoeffectiveness.
(For more details, see the materials on the topic “Solar cosmic rays”).
Coronal mass ejections (CMEs)
In the 90s In the 20th century, it became clear that an important source of geoeffective disturbances are not only solar flares, but also giant ejections of matter from the solar corona, the so-called coronal mass ejections (CMEs). Schematically, a CME looks like a closed magnetic field loop detached from the Sun, carrying a clump of coronal matter (see Figure 2).
Eruptive prominences
Eruptive prominences (EP)- these are large formations in the solar atmosphere, differing from the surrounding matter by increased density and low temperature; the most noticeable type of activity in the solar corona. The question of the degree of influence of prominences on space weather (direct or indirect, as one of the possible causes of the occurrence of (CME)) remains open today.
An example of an event when the decay of a filament (a filament is a prominence observed in the projection onto the solar disk) became the source of an increase in SCR fluxes in the near space is the event of April 14-17, 1994. But it should be noted that such events are relatively rare.
High-speed solar wind
The solar wind is bimodal, a mixture of slow and fast flows. The high-speed flow, in turn, is divided into quasi-stationary and sporadic flows, which have different natures. Quasi-stationary high-speed flows solar plasma responsible for recurrent geomagnetic disturbances are observed above coronal holes. The speed here is increased to 700-1000 km/s, the density is reduced (3-4 cm -3). Sporadic high-speed flows- relatively short-term and complex in structure formations responsible for sporadic magnetospheric disturbances, in particular, large magnetic storms are associated with them.
The speed of the solar wind in sporadic streams reaches 1200 km/s; a shock wave is formed at the leading edge and ahead of it.
Coronal holes
Coronal holes (CH)− these are regions of the solar corona with a relatively low temperature (0.8 × 10 6 K), low density and a magnetic field directed approximately radially from the Sun. In X-ray photographs, CDs appear dark compared to other regions of the corona (see figure). CHs seem to always exist in the polar regions of the Sun and sometimes continue into the region of low latitudes, where isolated CHs can form
Until the data from these two stations appeared, no one realized that coronal mass ejections were so important and widespread.
Since the eclipsing disk of the coronagraph cuts out the bright disk of the Sun from the field of view of the instrument, observations of the source of a coronal ejection on the solar surface using a coronagraph are impossible, and assumptions about its possible source are made based on observations by other instruments in other wavelengths. This fundamental difficulty leads to the fact that, from satellite observations near the Earth, in a number of cases it turns out to be impossible to determine the direction of movement of the ejecta: whether it is moving towards the Earth or away from the Earth. To overcome this difficulty, a pair of spacecraft of the STEREO project are currently used, which are separated at large angles in Earth's orbit.
see also
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Notes
Literature
- Brueckner G. E.(English) // Gordon Newkirk Jr. (ed.), Coronal Disturbances, IAU Symposium no. 57, held at Surfers Paradise, Queensland, Australia, 7-11 September, 1973, pp. 333–334, Reidel, Dordrecht; Boston. - 1974.
- Rainer Schwenn.(English) // Living Rev. Solar Phys. ( English), 3, (2006), 2. [Online article]. - 2006-2010.
- . Encyclopedia of the Sun. Laboratory of X-ray Solar Astronomy, Lebedev Physical Institute (TESIS).
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Excerpt characterizing Coronal Mass Ejections
“Remember that you will be responsible for all the consequences,” said Prince Vasily sternly, “you don’t know what you are doing.”- Vile woman! - the princess screamed, suddenly rushing at Anna Mikhailovna and snatching the briefcase.
Prince Vasily lowered his head and spread his arms.
At that moment the door, that terrible door that Pierre had been looking at for so long and which had opened so quietly, quickly and noisily fell back, banging against the wall, and the middle princess ran out of there and clasped her hands.
- What are you doing! – she said desperately. – II s"en va et vous me laissez seule. [He dies, and you leave me alone.]
The eldest princess dropped her briefcase. Anna Mikhailovna quickly bent down and, picking up the controversial item, ran into the bedroom. The eldest princess and Prince Vasily, having come to their senses, followed her. A few minutes later, the eldest princess was the first to emerge from there, with a pale and dry face and a bitten lower lip. At the sight of Pierre, her face expressed uncontrollable anger.
“Yes, rejoice now,” she said, “you have been waiting for this.”
And, bursting into tears, she covered her face with a handkerchief and ran out of the room.
Prince Vasily came out for the princess. He staggered to the sofa where Pierre was sitting and fell on it, covering his eyes with his hand. Pierre noticed that he was pale and that his lower jaw was jumping and shaking, as if in a feverish trembling.
- Ah, my friend! - he said, taking Pierre by the elbow; and in his voice there was a sincerity and weakness that Pierre had never noticed in him before. – How much do we sin, how much do we deceive, and all for what? I’m in my sixties, my friend... After all, for me... Everything will end in death, that’s it. Death is terrible. - He cried.
Anna Mikhailovna was the last to leave. She approached Pierre with quiet, slow steps.
“Pierre!...” she said.
Pierre looked at her questioningly. She kissed the young man's forehead, moistening it with her tears. She paused.
– II n "est plus... [He was gone...]
Pierre looked at her through his glasses.
- Allons, je vous reconduirai. Tachez de pleurer. Rien ne soulage, comme les larmes. [Come on, I'll take you with you. Try to cry: nothing makes you feel better than tears.]
She led him into the dark living room and Pierre was glad that no one there saw his face. Anna Mikhailovna left him, and when she returned, he, with his hand under his head, was fast asleep.
The next morning Anna Mikhailovna said to Pierre:
- Oui, mon cher, c"est une grande perte pour nous tous. Je ne parle pas de vous. Mais Dieu vous soutndra, vous etes jeune et vous voila a la tete d"une immense fortune, je l"espere. Le testament n"a pas ete encore ouvert. Je vous connais assez pour savoir que cela ne vous tourienera pas la tete, mais cela vous impose des devoirs, et il faut etre homme. [Yes, my friend, this is a great loss for all of us, not to mention you. But God will support you, you are young, and now you are, I hope, the owner of enormous wealth. The will has not yet been opened. I know you well enough and I am sure that this will not turn your head; but this imposes responsibilities on you; and you have to be a man.]
Pierre was silent.
– Peut etre plus tard je vous dirai, mon cher, que si je n"avais pas ete la, Dieu sait ce qui serait arrive. Vous savez, mon oncle avant hier encore me promettait de ne pas oublier Boris. Mais il n"a pas eu le temps. J "espere, mon cher ami, que vous remplirez le desir de votre pere. [Afterwards, perhaps I will tell you that if I had not been there, God knows what would have happened. You know that the uncle of the third day He promised me not to forget Boris, but he didn’t have time. I hope, my friend, you will fulfill your father’s wish.]
Pierre, not understanding anything and silently, blushing shyly, looked at Princess Anna Mikhailovna. After talking with Pierre, Anna Mikhailovna went to the Rostovs and went to bed. Waking up in the morning, she told the Rostovs and all her friends the details of the death of Count Bezukhy. She said that the count died the way she wanted to die, that his end was not only touching, but also edifying; The last meeting between father and son was so touching that she could not remember him without tears, and that she does not know who behaved better in these terrible moments: the father, who remembered everything and everyone in such a way in the last minutes and such Touching words were spoken to his son, or Pierre, whom it was a pity to see how he was killed and how, despite this, he tried to hide his sadness so as not to upset his dying father. “C"est penible, mais cela fait du bien; ca eleve l"ame de voir des hommes, comme le vieux comte et son digne fils,” [It’s hard, but it’s saving; the soul rises when you see people like the old count and his worthy son,” she said. She also spoke about the actions of the princess and Prince Vasily, not approving of them, but in great secrecy and in a whisper.
In Bald Mountains, the estate of Prince Nikolai Andreevich Bolkonsky, the arrival of the young Prince Andrei and the princess was expected every day; but the wait did not disrupt the orderly order in which life went on in the old prince’s house. General-in-Chief Prince Nikolai Andreevich, nicknamed in society le roi de Prusse, [the King of Prussia,] from the time he was exiled to the village under Paul, lived continuously in his Bald Mountains with his daughter, Princess Marya, and with her companion, m lle Bourienne. [Mademoiselle Bourien.] And during the new reign, although he was allowed entry into the capitals, he also continued to live in the countryside, saying that if anyone needed him, then he would travel one and a half hundred miles from Moscow to Bald Mountains, but what would he no one or anything is needed. He said that there are only two sources of human vices: idleness and superstition, and that there are only two virtues: activity and intelligence. He himself was involved in raising his daughter and, in order to develop both main virtues in her, until she was twenty, he gave her lessons in algebra and geometry and distributed her whole life in continuous studies. He himself was constantly busy either writing his memoirs, or calculating higher mathematics, or turning snuff boxes on a machine, or working in the garden and observing the buildings that did not stop on his estate. Since the main condition for activity is order, order in his way of life was brought to the utmost degree of precision. His trips to the table took place under the same unchanging conditions, and not only at the same hour, but also at the same minute. With the people around him, from his daughter to his servants, the prince was harsh and invariably demanding, and therefore, without being cruel, he aroused fear and respect for himself, which the most cruel person could not easily achieve. Despite the fact that he was retired and now had no importance in state affairs, every head of the province where the prince’s estate was, considered it his duty to come to him and, just like an architect, gardener or Princess Marya, waited for the appointed hour of the prince's appearance in the high waiter's room. And everyone in this waitress experienced the same feeling of respect and even fear, while the enormously high door of the office opened and the short figure of an old man in a powdered wig appeared, with small dry hands and gray drooping eyebrows, which sometimes, as he frowned, obscured the shine of smart people. and definitely young, sparkling eyes.
There is also a constant flow of particles in the form of the solar wind, unpredictable solar flares, and coronal mass ejections. All of them fall under the definition of “space weather”.
Sun spots
As you study the surface of the Sun, you can notice small dark areas on it. They vary in size and location. Typically, these spots are concentrated in areas above and below the equator. They are formed as a result of the interaction of plasma on the surface of the Sun with a magnetic field.
Sunspots are areas on the Sun whose temperature is significantly lower than other areas. The temperature in these areas reaches 3,527 degrees Celsius, which is almost 1,727 degrees less than in other parts of the Sun. However, don't let the numbers fool you. If we had the opportunity to contemplate one sunspot in the night sky, it would shine 10 times brighter than the full moon. When compared to the Sun, whose diameter is 1,392 million kilometers, sunspots may seem small in size. As a rule, these areas occupy less than 4% of the visible disk of the Sun. They are comparable to the diameter of Neptune, the smallest of the gas planets. However, the lifespan of sunspots, regardless of location, does not exceed several weeks.
The solar cycle, which refers to the cycle of solar activity, lasts 11 years. The last solar cycle began in January 2008 and reached its peak in 2013. Despite the low level of solar activity, scientists observed the largest sunspot in history in November 2014. It was comparable to Jupiter.
Solar flares
Intense magnetic fields in sunspot regions also lead to explosions known as solar flares. The energy is released outward with a force exceeding the energy release of millions of hydrogen bombs.
The temperature of the outer part of the solar atmosphere, known as the corona, typically reaches several million K at the time of solar flares. When solar flares pass the corona, they heat the gas to 10-20 million K, sometimes reaching a hundred million K. According to NASA , the energy released in a solar flare is “equivalent to the energy released by the simultaneous detonation of a million 100-megaton hydrogen bombs.”
The largest solar flares have a significant impact on the Earth. They can cause long-term radiation storms in the upper atmosphere and cause the cessation of radio communications. Moderate flares can also cause brief radio blackouts in polar regions and occasionally minor radiation storms.
Coronal mass ejections
During solar flares, the magnetic energy that accumulates in active regions on the Sun is mostly realized in the form of electromagnetic radiation. During coronal mass ejections, it is used to accelerate masses of matter in the solar crust.
Like solar flares, coronal mass ejections increase radiation in the outer layers of the Earth's atmosphere, affecting astronauts and radio signals. However, unlike flares, they also bring charged particles of matter that interact with the field surrounding our planet. The results of such interactions can vary depending on the size, speed and magnetic strength of the particles in question.
