Transition from a supersonic to a subsonic solar wind

The transition from a supersonic to a subsonic corona was investigated by increasing the density N sub O at the base of the corona while keeping the temperature T sub O constant. For the initial values of N sub O and T sub O, the solution of the inviscid solar wind equations is of the Parker type. As N sub O is increased, Parker type supersonic solutions cease to exist. No subsonic solutions exist.