The temperature reaches approximately6,000 degrees at the surface of the Sun and two to three million degrees at the corona, despite the fact that the latter is much further from the nucleus of the star, where the nuclear reactions that produce the heat take place. Hannes Alfven, a Swedish physicist who won the Nobel Prize in 1970, estimated that there were waves that carried this energy along lines of the magnetic field that travel through the plasma of the solar corona. But until today it had not been possible to detect the amount of waves of this type necessary to produce the required energy.
Now, high-definition ultraviolet images taken every eight seconds by NASA’s satelliteSolar Dymanics Observatory(SDO) have allowed Scott McIntosh and his colleagues at the American National Center for Atmospheric Research to detect large numbers of these waves. As explained by scientists in the latest issue of the magazineNature, the waves propagate at high speed (between 200 and 250 kilometers per second) in the moving plasma. These waves, whose energy flow is between 100 and 200 watts per square kilometer, “are capable of providing the energy necessary forpropel fast solar windsand thus compensate for the heat losses of the less agitated regions of the solar corona “, estimate the researchers.
However, according to McIntosh this is not enough to generate the2,000 watts per square meterThey are needed to supply the active areas of the crown. Therefore, instruments with higher spatial and temporal resolution would be needed to study the entire spectrum of energy radiated in the active regions of our star.
