The rise of a relatively cold plasma from the depths to the surface of the Sun appears as dark spots and occurs so slowly that it does not fit into theory.
Areas of high activity of the Sun - "nodes" of magnetism, visible to us as dark spots. They arise in places where the lines of force of magnetic fields rise to the surface, which carry with them the masses of colder plasma. Recent studies have shown that this movement is rather slow: at a speed of only 150 m / s. This work has been reported in Science Advances.
Aaron Birch and colleagues from Germany, the United Arab Emirates, the United States and Japan have studied the behavior of the Sun's magnetic fields using an HMI instrument operating on board the SDO space observatory. It continues to accumulate data on the star's magnetic activity without interruption since the launch of the probe in 2010. In parallel, the HMI captures the solar disk with high resolution in the visible range, allowing the study of horizontal plasma movements.
Simultaneously, the same processes were simulated on a computer: it was shown that the faster the plasma rises to the surface, the more noticeable the horizontal currents appear, which diverge from the exit point in all directions. However, comparing the readings of the model with observations, astronomers found that there are no really fast ascents and the updrafts cannot gain more than 150 m / s (based on a depth of 20 thousand km). The existing theoretical models say at least 500 m / s and, according to Aaron Birch and his co-authors, need to be revised.