Peak solar activity during the day. solar cycles. How to use the influence of the Sun

Our star changes from time to time, and this happens with a certain frequency. These periods are called solar cycles. The magnetic field of the star is responsible for the solar cycles. The rotation of the Sun differs from the rotation of solid bodies. Different regions of the star have different velocities, which determines the magnitude of the field. And it shows up in sunspots. Each cycle is characterized by a change in the polarity of the magnetic field.

Known activity cycles

eleven year old

This period of solar activity is the most famous and best studied. It is also called the Schwabe-Wolf law, paying tribute to the discoverer of this periodicity of the star. The name "eleven" is somewhat arbitrary for this cycle. Its duration, for example, in the 18th - 20th centuries ranged from 7 to 17 years, and in the 20th century the average value was 10.5 years. In the first four years of the cycle, there is an active increase in the number of sunspots. Flares, the number of fibers and prominences also become more frequent. In the next period (about seven years), the number of spots and activity decrease. 11-year cycles have different highs. They are usually measured in relative Wolf numbers. The 19th cycle was marked by the highest index for the entire observation period. Its value was 201 units, with a minimum of about 40.

twenty-two

In fact, this is a double Schwabe cycle. It links the spots and magnetic fields of the star. The sign of the magnetic field and the position of the magnetic polarities of sunspot groups change every 11 years. It takes two Schwabe cycles, or 22 years, to return the general magnetic field to its initial position.

century

This cycle lasts from 70 to 100 years. This is a modulation of eleven year cycles. In the middle of the last century there was a maximum of such a cycle, and the next one will take place in the middle of the current century. A two-century cyclicity is also noted. During its minima (periods of about 200 years), stable weakening of solar activity is observed. They last decades and are called global minima.

There are also cycles of 1000 and 2300 years.

Impact on our lives

According to M. Guhathakurta, NASA astrophysicist, not only solar maxima affect our lives, but minima too. The alternation of phases of changes in solar activity has its own specifics and harmful consequences. In solar cycles, at the maximum, the risks of failure in the operation of various equipment are exacerbated. More intense ultraviolet radiation heats the atmosphere, increasing its volume. The drag on the satellites and the ISS is increasing. They are more powerfully attracted to the Earth, and their orbits have to be adjusted. But there is some benefit from this: Because of the increased gravity, space debris also rushes towards the planet, burning up in dense atmospheric layers.

At cycle minimums, the intensity of ultraviolet radiation falls, and as a result, the atmosphere cools and decreases in volume. The solar wind is weakening, but the flow is increasing.

Data from Norwegian scientists have been published, from which it follows that people born in the year of the quiet Sun live longer by about 5 years. The birth and death times of 8,600 people were tracked in two locations from 1676 to 1878. This period was chosen because there are data for it for the 11-year cycle of solar activity. But the mechanism of influence of solar activity on life expectancy is not yet clear.

Global events taking place on our planet are closely related to the cyclicity of solar activity. The most famous epidemics of plague, cholera, as well as the frequency of floods and droughts fall precisely on the maxima of solar activity. Social upheavals are also associated with this phenomenon. Revolutions and big wars also fit into the cyclical system.

Cycle failures

But not everything fits into the cyclical framework. The sun has its own character, and sometimes its originality is manifested. For example, the 23rd solar cycle was supposed to end in 2007-2008. But it did not end, and what caused such a phenomenon is not yet clear. It turns out that solar cycles are an irregular regularity of our luminary.

In 2012, instead of the expected maximum activity, it fell below the level of 2011. The entire last level of solar activity is 4 times lower than the highest values ​​known over 260 years of observations.

From mid-2006 to mid-2009, the Sun was at a deep minimum. This period is characterized by several records of decline in activity. The lowest indicators of the speed of the solar wind were noted. The maximum number of days without spots was observed. Outbreak activity dropped to zero. From this follow possible options for the further behavior of the Sun. If we assume that in each cycle the star releases a certain amount of energy, then after several years of inactivity, it must throw this energy away. That is, the new cycle should be very fast and reach the highest values.

Extremely high maxima were not recorded for all the years of observations. But exceptional lows were noted. From this it follows that the failure of activity is a hint of a failure of the solar cycles.

The sun showed scientists a new secret - the peak of solar activity is too weak. Flares are rare, there are few sunspots. Scientists are afraid of a repetition, as 4 centuries ago, of the Maunder period. Then there were no flares and spots on the Sun for almost a hundred years, and a cooling began on the Earth.

- There was some failure in the activity of the Sun, - explains Vladimir Kuznetsov, director of the Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation. - The question is, can this happen again and when?

Filming of our Luminary in real time is carried out in different wavelengths. Forecasts of solar scientists, like weather forecasters, are also always calculated for several days. But, as the Center for Geomagnetic Situation notes, there are no mistakes.

Here you see small outliers of matter. It is not necessary to think that something dangerous will be due to this ejection, - Anatoly Belov, head of the IZMIRAN laboratory, comments on the images of solar activity. - Here you can predict a magnetic storm, somewhere around July 2-3.

It was precisely the center's accurate forecast in 2001 that helped to avoid the uncontrolled descent of the Mir station. The mass of the station was 120 tons. A little more than half burned up in the atmosphere. If the remaining fragments fell on populated areas, then disaster would not be avoided.

March 19 was a magnetic storm, which we predicted. For 2 days the station sank nine and a half kilometers. And it was decided to do everything quickly, and two days later it was successfully flooded, - says Sergey Gaydash, head of the IZMIRAN Space Weather Forecast Center.

The work of astronauts in orbit also directly depends on the forecast of solar activity. If the star is rampant, space walks are prohibited.

Three spacewalks are equivalent to a six-month expedition to the ISS, as the doctors seemed to say, - explains cosmonaut, ISS commander Gennady Padalka.

Today, astronauts are regularly in touch with the Ministry of Emergency Situations. From orbit, you can better see how merciless the Sun can be. Fires are raging again in Russia. Paradoxically, in the era of technological progress, people are increasingly dependent on the Sun. Flares can not only change the orbits of satellites and disable them, but also harm ground-based equipment, such as cellular communications.

Scientists admit that the accumulated knowledge is still too little. "The sun is far from being fully studied, a lot of incomprehensible things remain. Even such a simple thing as solar activity and its periodicity of 11 years. The reasons for it are unknown," Georgy Zastenker, chief researcher at the Space Research Institute of the Russian Academy of Sciences, throws up his hands.

Recently, specialists from the Space Research Institute, thanks to the Plasma-F experiment, made another discovery. The flow of the solar wind, that is, the substance that the Luminary loses in the process of a thermonuclear reaction, is unstable, changing in a split second, as if the Sun has its own breath. "If you water the garden with an ordinary hose, you have a stream of water that pours in a thick stream into one place, and if you attach a splitter, you get a set of streams that go at different angles. It turned out to be the same on the Sun," he found a decent an analogy for explaining solar phenomena Georgy Zastenker, chief researcher at the Space Research Institute of the Russian Academy of Sciences. This discovery is not a sensation, but one contribution to the treasury of knowledge about the red-hot giant.

Tel Aviv University Scientist Colin Price and his student Yuval Ruveni. They argue that ordinary lightning discharges on Earth are highly dependent on solar activity and can serve as indicators. In the Israeli Negev desert, Price and his research team, which also includes researchers from the United States, installed a sensitive antenna that receives signals from...

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... ] NCAR) under the leadership of Dr. Mausumi Dikpati, indicate that the next cycle solar activity will be 30 - 50% more powerful than the last one, already marked by a number of super-powerful cataclysms. By ... power lines. Dr. Dikpati's group to explain the many anomalies observed back in the previous cycle 23 solar activity in 2004 she developed the so-called Predictive Flux-transport Dynamo Model

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Has not appeared for 311 days. Pesnell says that such data indicate that the minimum of the next cycle has been reached. solar activity in 2008. For the first 90 days of 2009, our luminary did not show any significant activity for 78 days. In addition to this, the Ulysses research apparatus, which until recently conducted observations of the Sun, recorded ...

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Scientists at the Pulkovo Astronomical Observatory consider the impact of solar activity to a range of events, including global changes in weather and climate. About this to the correspondent, “... these flows pose a danger to astronauts and even to passengers of flights,” the director of the observatory said. According to the scientist, sunny activity modulates the flow of galactic cosmic rays, which affect the formation of the Earth's cloudiness and its reflectivity to the incoming from the Sun...

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There were almost no satellites, and dependence on telecommunications networks was much lower. Therefore, it is possible to predict with accuracy how high sunny activity will affect the life of the Earth, it is quite difficult. Some experts point out that on average once in 100 ... the infrastructure is difficult, but it is quite possible that we will experience them for ourselves. Based on the cycle solar activity, researchers suggest that similar "superstorms" may occur between 2010 and 2012. ...

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In 2008, it was predicted that it was the new cycle of 2008-2019 that would become a period of unprecedented solar activity. abnormal sunny activity provokes a lot of changes in the geomagnetic field of the Earth, at this time the intensity of electromagnetic increases ... regarding hypertensive crises, angina attacks, heart rhythm disturbances. In addition, during periods solar activity doctors are more likely to report heart attacks and strokes. People with cardiovascular diseases are especially affected. It...

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Completed and able to "give out" powerful flashes. Eleven year cycle solar activity associated with cyclic changes in the magnetic field in solar bowels. Outwardly, it manifests itself as a change in the number solar spots, frequencies of flares and prominences. In the transition from ... to which cycle this or that phenomenon belongs. As noted by the participants of the monitoring project solar activity, astrophysicists all over the world throughout the first half of 2009 tried to discern signs on the surface of the luminary ...

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Cycle solar activity. On Friday, officials from the US National Oceanic and Atmospheric Administration (NOAA) announced that they had discovered the first sunspot in the northern hemisphere of the Sun, marking the beginning of a new 11-year cycle. activity. During this period, the frequency of occurrence and number solar spots first increases and then decreases to a minimum, after which a new cycle begins activity. solar spots...

The Sun has been unusually "quiet" lately. The reason for the inactivity is revealed in the graph below.

Graph of the Wolf number from 2000 to 2019 (the red line shows the forecast). NOAA

As can be seen from the graph, there was a decline in the 11-year cycle of solar activity. Over the past two years, the number of sunspots has been decreasing as solar activity shifts from maximum to minimum. The decrease in the number of sunspots means that there are fewer solar flares and coronal mass ejections.

Photos of the Sun taken by the SOHO space observatory since 1996. NASA

Thus, the 24th solar cycle becomes the weakest in the last 100 years.

What is the 11 year activity cycle?

The eleven-year cycle, also called the Schwabe cycle or the Schwabe-Wolf cycle, is a prominent cycle of solar activity lasting approximately 11 years. It is characterized by a rather rapid (about 4 years) increase in the number of sunspots, and then a slower (about 7 years) decrease. The length of the cycle is not strictly equal to 11 years: in the 18th-20th centuries its length was 7-17 years, and in the 20th century it was about 10.5 years.

What is the Wolf number?

The Wolf number is a measure of solar activity proposed by the Swiss astronomer Rudolf Wolf. It is not equal to the number of spots currently observed on the Sun, but is calculated by the formula:

f the number of observed spots;
g number of observed sunspot groups;
k coefficient derived for each telescope with which observations are made.

Graph of average monthly Wolf numbers since 1750. Leland McInnes | Wikipedia

How calm is it really?

A common misconception is that space weather "freezes" and becomes uninteresting to observe during low solar activity. However, even during such periods there are many curious phenomena. For example, Earth's upper atmosphere is collapsing, allowing space debris to accumulate around our planet. The heliosphere is shrinking, causing the Earth to become more open to interstellar space. Galactic cosmic rays penetrate the inner solar system with relative ease.

Scientists are monitoring the situation as the number of sunspots continues to decline. As of March 29, the Wolf number is 23.

For eleven whole days, contrary to the well-known saying, there is not a single spot on the Sun. This means that our star is entering a period of minimum activity, and within the next year, magnetic storms and X-ray flares will become a rarity. About what happens to the Sun when its activity increases again and what explains these declines and rises, we asked Sergey Bogachev, an employee of the Laboratory of X-ray Solar Astronomy of the Lebedev Institute, Doctor of Physical and Mathematical Sciences, to tell us.

No sunspots today

The average monthly Wolf number on the Sun - the index by which scientists measure the number of sunspots - fell below 10 in the first three months of 2018. Prior to that, in 2017 it was at the level of 10-40, in a year earlier it reached 60 in some months. At the same time solar flares have almost ceased to occur on the Sun, and with them the number of magnetic storms on Earth tends to zero. All this indicates that our star is steadily moving towards the next minimum of solar activity - a state in which it finds itself approximately every 11 years.

The very concept of the solar cycle (and by it is meant just the periodic change of maxima and minima of solar activity) is fundamental to the physics of the Sun. For more than 260 years, since 1749, scientists have been monitoring the Sun on a daily basis and carefully recording the position of sunspots and, of course, their number. And, accordingly, for more than 260 years, periodic changes have been observed on these curves, somewhat similar to the beating of a pulse.

Each such "stroke of the solar heart" is assigned a number, and in total, since the beginning of observations, 24 such strokes have been observed. Accordingly, this is how many solar cycles are still familiar to mankind. How many of them were there in total, do they exist all the time while the Sun exists, or appear sporadically, do their amplitude and duration change, and how long, for example, did the solar cycle have in the time of the dinosaurs - there is no answer to all these questions, as well as to the question , whether the activity cycle is typical for all solar-type stars or exists only on some of them, and if so, whether two stars with the same radius and mass will have the same cycle period. We don't know this either.

Thus, the solar cycle is one of the most interesting solar mysteries, and although we know quite a lot about its nature, yet many of its fundamental foundations are still a mystery to us.

Graph of solar activity, measured by the number of sunspots, over the entire history of observations

The solar cycle is closely related to the presence of the so-called toroidal magnetic field in the Sun. Unlike the earth's magnetic field, which has the form of a magnet with two poles - north and south, the lines of which are directed from top to bottom, on the Sun there is a special type of field that is absent (or indistinguishable) on Earth - these are two magnetic rings with horizontal lines that encircle Sun. One is located in the northern hemisphere of the Sun, and the second in the southern, approximately symmetrically, that is, at the same distance from the equator.

The main lines of the toroidal field lie under the surface of the Sun, but some of the lines can float to the surface. It is in these places where the magnetic tubes of the toroidal field pierce the solar surface that sunspots appear. Thus, the number of sunspots in a sense reflects the strength (or more precisely, the flux) of the toroidal magnetic field on the Sun. The stronger this field, the larger the spots, the greater their number.

Accordingly, from the fact that once every 11 years spots on the Sun disappear, we can assume that once every 11 years the toroidal field disappears on the Sun. That is how it is. And actually this - the periodic appearance and disappearance of the solar toroidal field with a period of 11 years - is the cause of the solar cycle. The spots and their number are only indirect signs of this process.

Why is the solar cycle measured by the number of sunspots and not by the strength of the magnetic field? Well, at least because in 1749, of course, they could not observe the magnetic field on the Sun. The magnetic field of the Sun was discovered only at the beginning of the 20th century by the American astronomer George Hale, the inventor of the spectroheliograph, a device capable of measuring the profiles of the solar spectrum lines with high accuracy, including observing their splitting under the action of the Zeeman effect. Actually, this was not only the first measurement of the solar field, but in general the first detection of a magnetic field in an extraterrestrial object. So the only thing left for the astronomers of the 18th-19th centuries was to observe sunspots, and they had no way of even guessing about their connection with the magnetic field.

But why then do spots continue to be counted today, when multi-wavelength astronomy is developed, including observations from space, which, of course, provide much more accurate information about the solar cycle than a simple calculation of the Wolf number? The reason is very simple. Whatever modern cycle parameter you measure and no matter how accurate it is, this figure cannot be compared with the data of the 18th, 19th, and most of the 20th centuries. You simply won't understand how strong or weak your cycle is.

Last cycle of solar activity

SILSO data/image, Royal Observatory of Belgium, Brussels

The only way to make such a comparison is to count the number of spots, using exactly the same method and exactly the same formula as 200 years ago. Although it is possible that in 500 years, when significant series of new data on the number of flares and on radio emission fluxes will be accumulated, a number of sunspot numbers will finally lose their relevance and remain only as part of the history of astronomy. So far, this is not the case.

Knowing the nature of the solar cycle makes it possible to make some predictions about the number and location of sunspots, and even to pinpoint exactly when a new solar cycle begins. The latter statement may seem doubtful, since in a situation where the number of sunspots has decreased to almost zero, it seems impossible to confidently assert that the sunspot that was yesterday belonged to the previous cycle, and the sunspot today is already part of a new cycle. Nevertheless, there is such a way, and it is connected precisely with the knowledge of the nature of the cycle.

Since sunspots appear in those places where the surface of the Sun is pierced by lines of a toroidal magnetic field, each spot can be assigned a certain magnetic polarity - simply in the direction of the magnetic field. The spot can be "north" or "south". Moreover, since the magnetic field tube must pierce the surface of the Sun in two places, the spots must also predominantly form in pairs. In this case, the spot formed in the place where the lines of the toroidal field exit the surface will have a north polarity, and the spot paired with it, formed where the lines go back, will have a south polarity.

Since the toroidal field encircles the Sun like a ring and is directed horizontally, the pairs of spots are oriented predominantly horizontally on the disk of the Sun, that is, they are located at the same latitude, but one is ahead of the other. And since the direction of the field lines in all spots will be the same (after all, they are formed by one magnetic ring), then the polarities of all spots will be oriented in the same way. For example, the first, leading, spot in all pairs will be northern, and the second, lagging behind, southern.

The structure of magnetic fields in the region of sunspots

Such a pattern will be maintained as long as the given field ring exists, that is, all 11 years. In the other hemisphere of the Sun, where the symmetrical second ring of the field is located, the polarities will also persist for all 11 years, but have the opposite direction - the first spots will be the opposite, southern, and the second - northern.

What happens when the solar cycle changes? And there is a rather amazing thing called polarity reversal. The north and south magnetic poles of the Sun change places, and with them the direction of the toroidal magnetic field also changes. First, this field passes through zero, this is what is called the solar minimum, and then begins to recover, but with a different direction. If in the previous cycle the front spots in some hemisphere of the Sun had a northern polarity, then in the new cycle they will already have a southern one. This makes it possible to distinguish the spots of neighboring cycles from each other and to reliably fix the moment when a new cycle begins.

If we return to the events on the Sun right now, then we are witnessing the process of dying of the toroidal field of the 24th solar cycle. The remnants of this field still exist below the surface and even occasionally rise to the top (we see occasional faint spots these days), but in general they are the last traces of a dying "solar summer", like some of the last warm days in November. There is no doubt that in the coming months this field will finally die and the solar cycle will reach another minimum.