Solar Activity

Solar activity - a complex of phenomena that occur periodically in the atmosphere of the Sun. Their manifestation is closely related to the magnetic characteristics of the star plasma.

Solar activity in any zone begins with an increase in the magnetic flux in a separate section of the photosphere. After that, in the corresponding zones of the chromosphere, there is an increase in brightness in the lines of calcium and hydrogen. These zones are called flocculi. Approximately in the same areas of the photosphere, but somewhat deeper, there is also an increase in brightness in visible (white) light. These zones are called torches.

The increase in energy that is released in the flocculus and flare zone is the result of increased magnetic field strength.

Subsequently, solar activity is accompanied by the formation of spots. They are formed after one or two days after the formation of the floccula (in the form of pores - small black dots). Many of the flocculi disappear. However, some of them within two or three days pass into dark large formations.

Typical spot sizes are within a few tens of thousands of kilometers. In the structure of the spot there is a dark central part (shadow) and fibrous (penumbra).

The most important feature of sunspots is the presence in them of powerful magnetic fields. In the shadow area, they (fields) reach a tension of the order of several thousand extents.

The spots as a whole are represented by tubes of lines of force filling the photosphere, filling in the whole a few (or one) cells of the grid of the chromosphere. The upper part of the tube has an extension. In it lines of force diverge. Thus, around the shadow, they take a direction close to the horizontal.

The total pressure of the spot is included in the pressure in the magnetic field. Together with this, the total value is balanced by the degree of pressure of the surrounding photosphere. In this case, the magnetic field helps to suppress convective motions of the gas, through which energy is transferred from the depths upwards.

As a result, the temperature in the area of the spot is less than the surrounding temperature by about 1000 K. Thus, the spot is a chilled pit trapped in a magnetic field in the photosphere.

More often there are groups of such pits. Two spots are distinguished. One (smaller) is located in the east, the other (larger) is in the west. Between them and around them often there are many other small pits. A group of spots is called bipolar. This is due to the fact that two large wells always have opposite polarity in a magnetic field.

Flashes are considered to be the most powerful manifestation of the photosphere. In their essence they represent explosions, provoked by sudden compression in the plasma. This process (compression) develops under the influence of magnetic field pressure. As a result, a long plasma ribbon (or tourniquet) is formed.

Prominent formations in the atmosphere of the Sun are prominences. These relatively dense gas clouds arise in the corona or are ejected into it from the chromosphere. A typical prominence is a gigantic-sized luminous arch. This formation consists of a substance denser and colder than the surrounding chromosphere.

It should be noted that the total solar activity, which is characterized by the number and intensity of manifestation in the centers, periodically undergoes changes. To assess the level, the most simple and previously introduced method, the Wolf numbers, is used.

The time when the number of activity centers is the largest, is called the maximum. If their (centers of activity) is almost or not at all - a minimum. There are so-called cycles of solar activity. Maxima and minima alternate with the periodicity (on average) for eleven years.

The influence of solar activity on humans and other living beings has been actively studied by many scientists. A huge contribution was made by AL Chizhevsky. Using a fairly extensive material, the scientist showed a certain relationship between the largest and deadly epidemics and the maxima of solar activity.