THE FAST SOLAR WIND IN THE ACCELERATION REGION: OBSERVATIONALCONSTRAINTS FROM INTERPLANETARY SCINTILLATION MEASUREMENTS

摘要

The acceleration of the solar wind is still one of the outstandingrnproblems of solar physics. One difficulty is thernuncertainty in remote-sensing observations of solar windrnoutflow speeds when using proxies for solar wind velocityrnsuch as the drift velocity of density irregularities it isrnnot always obvious how these drift speeds relate to thatrnof the background solar wind. In particular, there is evidencernthat the turbulent-scale structures may be boostedrnabove the bulk flow speed by wave action in the fast windrnclose to the Sun. By combining different types of measurementrnwhich are sensitive to different scale sizes ofrnirregularity it is possible to investigate the effects of wavernaction, improving the accuracy to which the bulk flowrnspeed can be determined and providing information onrnthe wave field in the solar wind.