THE FAST SOLAR-WIND

A two-fluid model for the fast solar wind is described which attempts to account for observations at large distances and close to the Sun in coronal holes, allowing for anisotropic proton temperature, Alfven wa ve pressure and a realistic magnetic field, but neglecting the effects of proton heat conduction and viscosity. The resulting acceleration o f the wind near the Sun is quite rapid, although somewhat less so than in our previous models where the wave pressure was neglected. The pro ton temperatures in the corona remain relatively high and exceed the a ssociated wave ''temperature'' out to a heliocentric distance of about 5 solar radii. The proton temperature anisotropy may become very larg e if the effective particle scattering rate is small and it is suggest ed that in fact there may be significant particle-wave scattering in t he corona at least.