Coronal holes are the areas in the solar corona where plasma density and temperature are lowered. As a rule, the density in such areas is about a hundred times lower than in other areas of the crown. The appearance of coronal holes is recorded using images obtained in the x-ray range from satellites .
The appearance of coronal holes is associated with a period of remission - the time of minimal solar activity . Coronal holes are an important element of solar-terrestrial physics, leading to various effects of space weather , in particular to geomagnetic activity . Coronal holes are often the main factor affecting the Earth’s ionosphere and magnetic field . They are usually located in the polar regions of the Sun, but during the maximum period they can be observed at all latitudes.
They were first discovered by the results of observations on an X-ray telescope mounted on board the Skylab space station [1] .
Emergence Mechanism
As a rule, the lines of the magnetic field in the equatorial region of the Sun are closed, and thereby prevent the free flow of plasma into interplanetary space. However, a situation is possible when, as a result of various interactions between different beams of magnetic lines, they open. In this case, the plasma ceases to be held in the near-solar regions and rushes away from the Sun. In this area, its density and temperature drop - a coronal hole is formed. The "released" plasma becomes part of the solar wind .