Making the Corona and the Fast Solar Wind: A Self-consistent Simulation for the Low-Frequency Alfvén Waves from the Photosphere to 0.3 AU

Abstract

By performing a one-dimensional magnetohydrodynamic simulation with radiative cooling and thermal conduction, we show that the coronal heating and the fast solar wind acceleration in the coronal holes are natural consequences of the footpoint fluctuations of the magnetic fields at the photosphere. We initially set up a static open flux tube with a temperature of 10⁴ K rooted at the photosphere. We impose transverse photospheric motions corresponding to the granulations with a velocity <dv_⊥>=0.7 km s^-1 and a period between 20 s and 30 minutes, which generate outgoing Alfvén waves. We self-consistently treat these waves and the plasma heating. After attenuation in the chromosphere by ~=85% of the initial energy flux, the outgoing Alfvén waves enter the corona and contribute to the heating and acceleration of the plasma mainly by the nonlinear generation of the compressive waves and shocks. Our result clearly shows that the initially cool and static atmosphere is naturally heated up to 10⁶ K and accelerated to ~=800 km s^-1.