The Slow and Fast Solar Wind: Understanding Heating, Acceleration and Turbulence from Observations with Solar Probe Plus and Solar Orbiter

Abstract:

The Solar Probe Plus and Solar Orbiter missions have as part of their goals to understand the coronal heating and source regions of the solar wind and the role of turbulence in the solar wind acceleration and dynamics. In this presentation a summary of the questions associated with the distibution of wind speeds and magnetic fields in the inner heliosphere and their origin on the sun will be summarized. Where and how does the sharp gradient in speeds develop close to the Sun? Is the wind source for fast and slow the same, and is there a steady component or is its origin always intermittent in nature? Where does the heliospheric current sheet form and how stable is it close to the Sun? Where does Alfv\'enic turbulence form and what is its role in coronal heating? I will describe how the multiple Solar Probe Plus passes together with Solar Orbiter alignments and quadratures will help to make fundamental progress on these questions.