An Analysis of the energy balance in the solar wind formation region

Abstract

The non-thermal broadening of coronal lines observed within short distances from the Sun was analysed and analysis revealed that near the Sun this broadening is caused by Alfven waves. Within the magnetohydrodynamic (MHD) approximation, the wave energy flux required for solar wind formation, and also the plasma velocity and temperature were calculated. Electron density distributions and flow geometry were used as input data. It is shown that the energy flux required for solar wind formation enters the solar corona in the form of Alfven waves and the dissipation of these waves provides the heating of the solar wind plasma near the Sun. The transformation of Alfven waves to acoustic waves in this region is less effective than their dissipation. The dissipation of the Alfven waves falls off with distance from the Sun, and the heating of the solar wind plasma is determined by the coefficient of transformation of the Alfven waves to acoustic waves. Subsequently, the dissipation effectiveness of the acoustic waves decreases, and the absorption coefficient of acoustic waves becomes less than the transformation coefficient of the Alfven waves to acoustic waves; plasma heating is now determined by the absorption of acoustic waves.

Keywords:

• Sun
• Corona (Sun)
• Solar wind

Additional information

Notes on contributors

S. I. Molodykh

Email: [email protected]