The solar wind is a flow of plasma primarily made up of Ion S and electron S which is ejected high atmosphere Sun. For the star S other than the Sun, one generally speaks about stellar wind .

In the Solar system, the composition of this plasma is identical to that of the solar Couronne: 73% of Hydrogen and 25% of Helium. The Sun loses approximately 1 × 10 9 kg of matter a second in the form of solar wind. In the overheated crown of the sun (1 million degrees) of the hydrogen atoms are ionized, which confers an electric charge to them. This extreme plasma is then expelled at a considerable speed. The speed of the solar wind varies from 400 to 800 km/S (of: 1,440,000 with: 2,880,000 km/h), the Average being of 450 km/s (: 1,620,000 km/h). The flows of solar wind are known as rapids in the coronaux holes, generally located at the level of the poles where the lines of magnetic field are open. A contrario, the flows of solar wind is known as slow on the level of the equatorial plan.

The solar wind being a plasma, it is subject to the influence of the solar Magnetic field. Because of the combination of the radial movement of the particles and rotation of the Sun, the solar lines of magnetic field form a spiral (the spiral of Parker). The solar wind, pulled by the lines of magnetic field, marries the form of the latter.

The particularly energy gusts of solar wind caused by solar eruptions, ejections of mass coronale and other phenomena are called solar storms . Those can subject the space probes and the satellite S to great amounts of radiations and can also strongly disturb the transmission of the electromagnetic signals like those of the radio and television, to cause currents induced in the pipelines (and thus to accelerate their corrosion). They can finally generate continuous currents on the lines with high voltage big lengths, which cause overheatings in the Transformateur S of the electric stations (in 1989, with the Canada, surroundings six million people was found without electricity because of a magnetic storm). During an solar eruption, the number of particles reaching the terrestrial atmosphere is of: 10,000 (to be compared with 10 particles in the absence of irruption).

The particles of the solar wind trapped in the Terrestrial magnetic field tend to accumulate in the Ceinture of Van Allen and cause the polar lights when they penetrate in the Terrestrial atmosphere near the poles. The terrestrial Magnétosphère is opposed to the solar wind like does it an abutment of bridge with respect to the current of the river, it protects us from the solar wind and acts like a shield. The magnetosphere, which should resemble a dipole, is deformed by the solar wind. It is compressed diurnal side whereas it extends to long distances from the night side. Others Planet S having a magnetic field have also their own dawn; Neptune is an example. The solar wind is also responsible for the second tail of the Comet S. This tail, made up of plasma, is always directed contrary to the Sun (like a shade).

The Pression of the solar wind creates a “bubble” in the interstellar Milieu. The limit to which the solar wind is not able any more to push back the interstellar environment is called Héliopause and is often regarded as the “border” of the solar system. The distance from the héliopause is not known with precision and probably varies considerably with the current speed of the solar wind and the local density of the interstellar environment, but it is known that it is located much further the Orbite from Pluton.

An attempt at collection of dust from solar wind was tried by the launching of a probe (mission Genesis) but the recovery of the samples proves to be delicate following the crash landing on Earth of the capsule the container.

See too

Related articles

• Magnetosphere
• Ionosphere
• solar Veil

External bonds

• NASA: To listen to the solar wind
• NOAA: Characteristics of the solar wind during the last 24 hours