Comparisons of interplanetary scintillation and optical measurements of solar wind acceleration with model results

Observations of the fast, high latitude solar wind show that acceleration of the fast wind is complete by 10 solar radii (R), while measurements from the LASCO instrument on SOHO show that most of the acceleration takes place inside 5 R. A series of observations were made in September 1997 using EISCAT and the C2 and C3 coronagraphs aboard SOHO to measure the solar wind velocity profile from 3 R out to beyond 30 R. The overlapping fields of view of the instruments allowed direct comparisons to be made between IPS and optical estimations of flow velocity. Together, these measurements provide strong constraints on any model seeking to provide an explanation of the acceleration of the fast solar wind. We present the results of a comparison between out observations and the most recent version of the Lindau-Warsaw solar wind acceleration model. © 2000 COSPAR. Published by Elsevier Science Ltd.