It can be used not only as a propulsion device for space sailing ships, but also as a source of energy. The most famous use of the solar wind in this capacity was first proposed by Freeman Dyson, who suggested that a highly developed civilization could create a sphere around a star that would collect all the energy it emits. Proceeding from this, another method of searching for extraterrestrial civilizations was also proposed.

Meanwhile, a more practical concept for harnessing solar wind energy - the Dyson-Harrop satellites - was proposed by a team of researchers at Washington State University led by Brooks Harrop. They are fairly simple power plants that collect electrons from the solar wind. A long metal rod aimed at the sun is energized to generate a magnetic field that will attract electrons. At the other end is an electron trap-receiver, consisting of a sail and a receiver.

According to Harrop's calculations, a satellite with a 300-meter rod, 1 cm thick and a 10-meter trap will be able to “collect” up to 1.7 MW in Earth orbit. This is enough to power approximately 1,000 private houses. The same satellite, but with a kilometer-long rod and a sail of 8400 kilometers, will be able to “collect” already 1 billion billion gigawatts of energy (10 27 W). It remains only to transfer this energy to the Earth in order to abandon all its other types.

Harrop's team suggests transmitting energy using a laser beam. However, if the design of the satellite itself is quite simple and quite feasible at the modern level of technology, then the creation of a laser "cable" is still technically impossible. The fact is that in order to effectively collect the solar wind, the Dyson-Harrop satellite must lie outside the plane of the ecliptic, which means it is located millions of kilometers from the Earth. At this distance, the laser beam will produce a spot thousands of kilometers in diameter. An adequate focusing system would require a lens 10 to 100 meters in diameter. In addition, many dangers cannot be excluded from possible system failures. On the other hand, energy is required in space itself, and the small satellites of Dyson-Harrop may well become its main source, replacing solar panels and nuclear reactors.

SUNNY WIND- a continuous flow of plasma of solar origin, spreading approximately radially from the Sun and filling the solar system to heliocentric. distances R ~ 100 AU. e. C. in. formed when gasdynamic. expansion of the solar corona (see. The sun) into interplanetary space. At high temperatures pax, which exist in the solar corona (1.5 * 10 9 K), the pressure of the overlying layers cannot balance the gas pressure of the corona matter, and the corona expands.

The first evidence of the existence of post. plasma flux from the Sun were obtained by L. Biermann in the 1950s. on the analysis of forces acting on plasma tails of comets. In 1957, Y. Parker (E. Parker), analyzing the conditions of equilibrium of the corona substance, showed that the corona cannot be under hydrostatic conditions. equilibrium, as previously assumed, but should expand, and this expansion under the existing boundary conditions should lead to the acceleration of coronal matter to supersonic speeds (see below). For the first time, a plasma flow of solar origin was recorded on the Soviet space mission. apparatus "Luna-2" in 1959. The existence of post. the outflow of plasma from the Sun was proved as a result of many months of measurements on Amer. cosm. apparatus "Mariner-2" in 1962.

Wed S.'s characteristics. are given in table. 1. Streams S. in. can be divided into two classes: slow - with a speed of 300 km / s and fast - with a speed of 600-700 km / s. Fast currents emanate from areas of the solar corona, where the structure of the magn. the field is close to radial. Some of these areas are coronal holes... Slow streams of S. to. connected, apparently, with areas of the crown, in which there is, therefore, a tangential component of magn. fields.

Tab. 1.- Average characteristics of the solar wind in the Earth's orbit

Tab. 2.- The relative chemical composition of the solar wind

In addition to the main. of the components of S. v. - protons and electrons; ions of oxygen, silicon, sulfur, iron (Fig. 1). When analyzing gases trapped in foils exposed on the Moon, atoms of Ne and Ar were found. Wed relative chem. S.'s composition of century is given in table. 2. Ionization. state of matter C. corresponds to the level in the corona where the recombination time is short compared to the expansion time Measurements of ionization temperature of S.'s ions of century. allow you to determine the electronic temperature of the solar corona.

In S. in. there are decomp. types of waves: Langmuir, whistlers, ion-sound, magnetosonic, Alfvén, etc. (see. Plasma waves Some of the waves of the Alfvén type are generated on the Sun, and some are excited in the interplanetary medium. The generation of waves smooths out the deviations of the f-tions of the distribution of particles from Maxwellian and, in conjunction with the effect of magn. field on the plasma leads to the fact that S. century. behaves like a continuous medium. Waves of the Alfvén type play an important role in the acceleration of small components of the shock wave. and in the formation of the f-tion of the distribution of protons. In S. in. contact and rotational discontinuities are also observed, which are characteristic of magnetized plasma.

Rice. 1. Mass spectrum of the solar wind. The horizontal axis is the ratio of the particle mass to its charge, the vertical axis is the number of particles registered in the energy window of the device for 10 s. Numbers with a "+" sign indicate the charge of the ion.

C. stream. is supersonic in relation to the speeds of those types of waves, to-rye provide eff. transmission of energy to S. century. (Alfvén, sound and magnetosonic waves). Alfven and sound Mach number C.v. in the orbit of the Earth 7. When flowing around the S. v. obstacles capable of effectively deflecting it (the magnetic fields of Mercury, Earth, Jupiter, Saturn or the conducting ionospheres of Venus and, apparently, Mars), a detached bow shock wave is formed. C. in. decelerates and heats up at the front of the shock wave, which allows it to flow around the obstacle. Moreover, in S. century. a cavity is formed - a magnetosphere (intrinsic or induced), the shape and size of the cut are determined by the pressure balance of the magnets. fields of the planet and the pressure of the flowing plasma flow (see. Magnetosphere of the Earth, Magnetospheres of planets)... In the case of S.'s interaction of century. with a non-conducting body (for example, the Moon), the shock wave does not arise. The plasma flow is absorbed by the surface, and a cavity is formed behind the body, which is gradually filled with sulfuric plasma.

The stationary process of corona plasma outflow is superimposed by non-stationary processes associated with flares on the sun... With strong flares, matter is ejected from the bottom. regions of the corona into the interplanetary medium. In this case, a shock wave is also formed (Fig. 2), edges gradually slows down, spreading in S.'s plasma of century. The arrival of a shock wave to the Earth causes compression of the magnetosphere, after which the development of magnes usually begins. storms (see. Magnetic variations).

Rice. 2. Propagation of interplanetary shock waves and ejection from a solar flare. Arrows show the direction of motion of the solar wind plasma, lines without signature - lines of force of the magnetic field.

Rice. 3. Types of solutions of the corona expansion equation. The speed and distance are normalized to the critical speed v k and the critical distance R k. Solution 2 corresponds to the solar wind.

The expansion of the solar corona is described by the system of equations for the conservation of mass, the moment of the number of motion and the energy equation. Solutions for dec. the nature of the change in speed with distance are shown in Fig. 3. Solutions 1 and 2 correspond to low velocities at the base of the crown. The choice between these two solutions is determined by the conditions at infinity. Solution 1 corresponds to low rates of expansion of the corona and gives large values ​​of pressure at infinity, i.e., it meets the same difficulties as the static model. crowns. Solution 2 corresponds to the transition of the expansion rate through the values ​​of the speed of sound ( v to) on a certain critical. distance R to and subsequent expansion at supersonic speed. This solution gives a vanishingly small value of pressure at infinity, which makes it possible to match it with the low pressure of the interstellar medium. The course of this type was named by J. Parker by S. in. Critical the point is above the surface of the Sun if the temperature of the corona is less than a certain critical value. meaning , where m is the proton mass, is the adiabatic exponent, and is the mass of the Sun. In fig. 4 shows the change in the expansion rate from heliocentric. distance depending on temperature isothermal isotropic corona. Subsequent models of S. in. take into account variations in the coronal temperature with distance, the two-fluid nature of the medium (electron and proton gases), thermal conductivity, viscosity, nonspherical. the nature of the expansion.

Rice. 4. Profiles of the solar wind velocity for the isothermal corona model at different values ​​of the coronal temperature.

C. in. provides basic outflow of thermal energy of the corona, since heat transfer to the chromosphere, electromagnet. corona radiation and electronic thermal conductivity of S. century. insufficient to establish the thermal balance of the crown. Electronic thermal conductivity provides a slow decrease in the temperature of S. in. with distance. C. in. does not play any significant role in the energy of the Sun as a whole, since the energy flow carried away by it is ~ 10 -7 luminosity The sun.

C. in. carries with it to the interplanetary medium the coronal magn. field. The lines of force of this field frozen into the plasma form an interplanetary magn. field (MMP). Although the intensity of the IMF is low and its energy density is approx. 1% of the density kinetic. energy of a semiconductor, it plays an important role in thermodynamics of semiconductor voltages. and in the dynamics of S.'s interactions. with the bodies of the solar system, as well as the streams of the S. century. between themselves. Combination of S.'s expansion. with the rotation of the sun leads to the fact that magn. the lines of force frozen in in S. century have a shape close to the spiral of Archimedes (Fig. 5). Radial B R and azimuthal components of magn. fields change differently with distance near the plane of the ecliptic:

where is ang. the speed of rotation of the sun, and is the radial component of the velocity of the S. of speed, index 0 corresponds to the initial level. At the distance of the Earth's orbit, the angle between the direction of magn. fields and R about 45 °. At large A magn. the field is almost perpendicular to R.

Rice. 5. The shape of the line of force of the interplanetary magnetic field. is the angular velocity of rotation of the Sun, and is the radial component of the plasma velocity, R is the heliocentric distance.

S. century, arising over the regions of the Sun with decomp. orientation magn. fields, forms flows with differently oriented IMF. Separation of the observed large-scale structure of S. of century. for an even number of sectors with diff. the direction of the radial component of the permafrost is called. interplanetary sector structure. S.'s characteristics. (speed, temp-pa, particle concentration, etc.) also in cf. naturally change in the cross section of each sector, which is associated with the existence of a fast stream of S. v. inside the sector. The boundaries of the sectors are usually located within the slow flow of S. to. Most often, 2 or 4 sectors are observed rotating with the Sun. This structure, which is formed during S.'s pulling of century. large-scale magn. fields of the corona, can be observed for several. revolutions of the sun. The IMF sector structure is a consequence of the existence of a current sheet (TC) in the interplanetary medium, which rotates with the Sun. TC creates a jump in magn. fields - the radial components of the IMF have different signs on opposite sides of the TS. This TS, predicted by H. Alfven (N. Alfven), passes through those parts of the solar corona, which are associated with active regions on the Sun, and separates the indicated regions with decomp. signs of the radial component of the solar magn. fields. TS is located approximately in the plane of the solar equator and has a folded structure. The rotation of the Sun leads to the twisting of the TS folds in a spiral (Fig. 6). Being near the plane of the ecliptic, the observer turns out to be either higher or lower than the TS, due to which he finds himself in sectors with different signs of the radial IMF component.

Near the Sun in the northern century. there are longitudinal and latitudinal velocity gradients due to the difference in the velocities of fast and slow streams. With distance from the Sun and the steepening of the boundary between the streams in the north. radial velocity gradients arise, which lead to the formation collisionless shock waves(fig. 7). First, a shock wave is formed, propagating forward from the boundary of the sectors (direct shock wave), and then a backward shock wave propagating to the Sun is formed.

Rice. 6. The shape of the heliospheric current sheet. Its intersection with the plane of the ecliptic (inclined to the equator of the Sun at an angle of ~ 7 °) gives the observed sector structure of the interplanetary magnetic field.

Rice. 7. The structure of the interplanetary magnetic field sector. Short arrows show the direction of the solar wind plasma flow, lines with arrows - magnetic field lines, dash-dot line - sector boundaries (intersection of the plane of the figure with the current sheet).

Since the velocity of the shock wave is less than the velocity of the solar arc, the plasma carries the backward shock wave away from the sun. Shock waves near the boundaries of the sectors are formed at distances of ~ 1 AU. e. and can be traced to distances of several. a. e. These shock waves, as well as interplanetary shock waves from solar flares and near-planetary shock waves, accelerate particles and are, thus, a source of energetic particles.

C. in. extends to distances of ~ 100 AU. e., where the pressure of the interstellar medium balances the dynamic. S.'s pressure in. The cavity swept out by S. century. in the interstellar medium, forms the heliosphere (see. Interplanetary environment The expanding S. century. together with the magnesium frozen into it. field prevents galactic penetration into the solar system. cosm. rays of low energies and leads to variations in cosmic. rays of high energies. A phenomenon analogous to S. of century has also been found in some other stars (see. Stellar wind).

Lit .: Parker E. N., Dynamic processes in the interplanetary medium, trans. from English, M., 1965; B r and d t J., Solar wind, trans. from English., M., 1973; Hundhausen A., Corona expansion and solar wind, trans. from English, M., 1976. O. L. Vaysberg.

Concept sunny wind was introduced into astronomy at the end of the 40s of the 20th century, when the American astronomer S. Forbush, measuring the intensity of cosmic rays, noticed that it significantly decreases with an increase in solar activity and falls very sharply during.

It seemed rather strange. Rather, the opposite might have been expected. After all, the Sun itself is the supplier of cosmic rays. Therefore, it would seem that the higher the activity of our daylight, the more particles it should throw into the surrounding space.

It remained to assume that the increase in solar activity affects in such a way that it begins to deflect particles of cosmic rays - to discard them.

It was then that the assumption arose that the perpetrators of the mysterious effect are streams of charged particles escaping from the surface of the Sun and penetrating the space of the solar system. This peculiar solar wind also cleans the interplanetary medium, "sweeping" particles of cosmic rays out of it.

This hypothesis was also supported by the phenomena observed in. As you know, cometary tails are always directed away from the Sun. Initially, this circumstance was associated with the light pressure of the sun's rays. However, it was found that light pressure alone cannot cause all the phenomena that occur in comets. Calculations have shown that the formation and observed deflection of cometary tails requires the action of not only photons, but also particles of matter.

As a matter of fact, it was known before that the Sun throws out streams of charged particles - corpuscles. However, such flows were assumed to be sporadic. But cometary tails are always directed in the opposite direction from the Sun, and not only during periods of amplification. This means that the corpuscular radiation filling the space of the solar system must exist constantly. It increases with increasing solar activity, but it always exists.

Thus, the solar wind continuously blows the space around the sun. What does this solar wind consist of, and under what conditions does it arise?

The outermost layer of the solar atmosphere is the "corona". This part of the atmosphere of our daylight is unusually rarefied. But the so-called "kinetic temperature" of the corona, determined by the speed of particle motion, is very high. It reaches a million degrees. Therefore, coronal gas is completely ionized and is a mixture of protons, ions of various elements and free electrons.

Recently, it was reported that the solar wind contains helium ions. This circumstance sheds light on the mechanism by which charged particles are ejected from the surface of the Sun. If the solar wind consisted only of electrons and protons, then it would still be possible to assume that it is formed due to purely thermal processes and is something like steam formed above the surface of boiling water. However, the nuclei of helium atoms are four times heavier than protons and are therefore unlikely to be ejected by evaporation. Most likely, the formation of the solar wind is associated with the action of magnetic forces. Flying away from the Sun, the plasma clouds seem to carry away with them the magnetic fields. It is these fields that serve as a kind of "cement" that "binds" together particles with different masses and charges.

Observations and calculations carried out by astronomers have shown that with distance from the Sun, the density of the corona gradually decreases. But it turns out that in the region of the Earth's orbit it is still noticeably different from zero. In other words, our planet is located inside the solar atmosphere.

If the corona is more or less stable near the Sun, then as the distance increases, it tends to expand into space. And the farther from the Sun, the higher the rate of this expansion. According to the calculations of the American astronomer E. Parker, already at a distance of 10 million km coronal particles move at speeds exceeding their speed.

Thus, the conclusion suggests itself that the solar corona is the solar wind blowing over the space of our planetary system.

These theoretical conclusions were fully confirmed by measurements on space rockets and artificial earth satellites. It turned out that the solar wind always exists near the Earth - it "blows" at a speed of about 400 km / sec.

How far does the solar wind blow? With theoretical considerations, in one case, it turns out that the solar wind subsides already in the orbital region, in the other - that it still exists at a very large distance beyond the orbit of the last planet Pluto. But these are only theoretically the extreme limits of the possible propagation of the solar wind. Only observations can indicate the exact boundary.

The Sun's atmosphere is 90% hydrogen. Its most distant part from the surface is called the Sun's corona, and it is clearly visible during total solar eclipses. The corona temperature reaches 1.5-2 million K, and the corona gas is fully ionized. At such a plasma temperature, the thermal velocity of protons is on the order of 100 km / s, and of electrons - several thousand kilometers per second. To overcome the solar attraction, an initial speed of 618 km / s, the second cosmic speed of the Sun, is sufficient. Therefore, there is a constant leakage of plasma from the solar corona into space. This flow of protons and electrons is called the solar wind.

Having overcome the attraction of the Sun, the particles of the solar wind fly along straight trajectories. The speed of each particle almost does not change with removal, but it can be different. This speed depends mainly on the state of the solar surface, on the "weather" on the Sun. On average, it is equal to v ≈ 470 km / s. The solar wind passes the distance to the Earth in 3-4 days. In this case, the density of particles in it decreases inversely proportional to the square of the distance to the Sun. At a distance equal to the radius of the earth's orbit, in 1 cm 3 there are on average 4 protons and 4 electrons.

The solar wind reduces the mass of our star - the Sun - by 10 9 kg per second. Although this number seems large on terrestrial scales, it is actually small: the decrease in solar mass can be seen only for times thousands of times longer than the current age of the Sun, which is approximately 5 billion years.

The interaction of the solar wind with a magnetic field is interesting and unusual. It is known that charged particles usually move in a magnetic field H along a circle or along helical lines. This is true, however, only when the magnetic field is strong enough. More precisely, for the movement of charged particles in a circle, the energy density of the magnetic field H 2 / 8π must be greater than the kinetic energy density of the moving plasma ρv 2/2. In the solar wind, the situation is the opposite: the magnetic field is weak. Therefore, charged particles move in straight lines, and the magnetic field is not constant, it moves with the flow of particles, as if carried away by this flow to the periphery of the solar system. The direction of the magnetic field in the entire interplanetary space remains the same as it was on the surface of the Sun at the time of the exit of the solar wind plasma.

The magnetic field, as a rule, changes its direction 4 times when walking along the equator of the Sun. The sun rotates: points at the equator complete a revolution in T = 27 days. Therefore, the interplanetary magnetic field is directed along spirals (see Fig.), And the whole picture of this figure rotates following the rotation of the solar surface. The angle of rotation of the Sun changes as φ = 2π / T. The distance from the Sun increases with the speed of the solar wind: r = vt. Hence the equation of the spirals in Fig. has the form: φ = 2πr / vT. At a distance of the earth's orbit (r = 1.5 10 11 m), the angle of inclination of the magnetic field to the radius vector is, as it is easy to check, 50 °. On average, such an angle is measured by spacecraft, but not very close to the Earth. In the vicinity of planets, the magnetic field is arranged differently (see Magnetosphere).

Imagine hearing the announcer's words in the weather forecast: “Tomorrow the wind will increase dramatically. In this regard, interruptions in the operation of radio, mobile communications and the Internet are possible. A space mission has been postponed in the United States. Intense auroras are expected in the north of Russia ... ”.


You will be surprised: what nonsense, what does the wind have to do with it? And the fact is that you missed the beginning of the forecast: “There was a flash on the Sun last night. A powerful stream of the solar wind moves to the Earth ... ".

Ordinary wind is the movement of air particles (molecules of oxygen, nitrogen and other gases). A stream of particles rushes from the Sun too. It is called the solar wind. If you do not delve into hundreds of cumbersome formulas, calculations and heated scientific disputes, then, in general, the picture appears to be like this.

Inside our luminary, thermonuclear reactions are taking place, heating this huge ball of gases. The temperature of the outer layer - the solar corona - reaches a million degrees. This makes the atoms move at such a speed that, when they collide, they smash each other to smithereens. It is known that the heated gas tends to expand, to occupy a larger volume. Something similar is happening here. Particles of hydrogen, helium, silicon, sulfur, iron and other substances scatter in all directions.

They are gaining ever greater speed and in about six days they reach the near-earth boundaries. Even if the sun was calm, the speed of the solar wind here reaches 450 kilometers per second. Well, when the solar flare erupts a huge fiery bubble of particles, their speed can reach 1200 kilometers per second! And you can't call it a refreshing "breeze" - about 200 thousand degrees.

Does a person feel the solar wind?

Indeed, since the stream of hot particles rushes constantly, why don't we feel how it "blows" over us? Let's say the particles are so small that the skin does not feel their touch. But they are not noticed even by terrestrial devices. Why?

Because the Earth is protected from solar vortices by its magnetic field. The stream of particles, as it were, flows around it and rushes on. Only on days when solar emissions are especially powerful does our magnetic shield have a hard time. A solar hurricane blows through it and bursts into the upper atmosphere. Alien particles summon. The magnetic field is sharply deformed, forecasters talk about "magnetic storms".


Because of them, space satellites go out of control. Airplanes disappear from the radar screens. Radio waves are interfered with and communication is disrupted. On such days, satellite dishes are turned off, flights are canceled, "communication" with spacecraft is interrupted. An electric current is suddenly generated in power grids, railroad rails, pipelines. From this, traffic light signals switch by themselves, gas pipelines rust, disconnected electrical appliances burn out. Plus, thousands of people feel discomfort and ailments.

The cosmic effects of the solar wind can be detected not only during solar flares: it, albeit weaker, but blows constantly.

It has long been noted that a comet's tail grows as it approaches the Sun. It causes the frozen gases that form the cometary nucleus to evaporate. And the solar wind carries these gases in the form of a plume, always directed in the direction opposite to the Sun. So the earthly wind unfolds the smoke from the chimney and gives it one form or another.

In years of increased activity, the exposure of the Earth to galactic cosmic rays drops sharply. The solar wind is gaining such strength that it simply sweeps them to the outskirts of the planetary system.

There are planets in which the magnetic field is very weak, or even completely absent (for example, on Mars). Here, nothing prevents the solar wind from walking. Scientists believe that it was he who almost "blew" its atmosphere from Mars for hundreds of millions of years. Because of this, the orange planet lost sweat and water and, possibly, living organisms.

Where does the solar wind subside?

Nobody knows the exact answer yet. Particles fly to the vicinity of the Earth, gaining speed. Then it gradually falls, but it seems that the wind reaches the farthest corners of the solar system. Somewhere there it weakens and is inhibited by the rarefied interstellar matter.

So far, astronomers cannot say exactly how far this is going. To answer, you need to catch the particles, flying farther and farther from the Sun, until they no longer come across. By the way, the limit where this happens can be considered the boundary of the solar system.


Spacecraft, which are periodically launched from our planet, are equipped with traps for the solar wind. In 2016, the streams of the solar wind were captured on video. Who knows if he will not become the same familiar "character" of weather reports as our old friend - the earthly wind?