On the acceleration and wave heating of the solar wind: implications of the mean free path of solar energetic particles

Abstract

Wave damping and cascading processes have been found to be important for the heating and acceleration of the solar wind. However, it remains a difficult task to extract details of these processes from observations of the thermal plasma only. The wave power required for efficient heating and acceleration of the solar wind also affects the acceleration and transport of solar energetic particles. Thus, their observation could provide valuable clues for the actual evolution of the wave power close to the coronal base and, in turn, give constraints for solar wind modeling. Pursuing this idea, we have developed a steady‐state two‐fluid model for the wave heating and acceleration of the solar wind. The dissipation frequency determining the heating is obtained from a cyclotron damping rate that depends on the plasma beta and, thus, differs from the usual assumption, a fixed fraction of the ion cyclotron frequency. We present first results obtained with the two‐fluid code and, in particular, discuss the implications of the corresponding mean free path of energetic particles.