COUPLING OF THE CORONAL HE ABUNDANCE TO THE SOLAR-WIND

Models of the transition region - corona - solar wind system are inves tigated in order to find the coronal helium abundance and to study the role played by coronal helium in controlling the the solar wind proto n flux. The thermal force on alpha-particles in the transition region sets the flow of helium into the corona. The frictional coupling betwe en alpha-particles and protons and/or the electric polarization field determines the proton flux in the solar wind as well as the fate of th e coronal helium content.