Source Regions of the Slow Solar Wind

While the fast solar wind is nerally thought to originate from coronal holes, the ~, Oa% source of the slow solar wind is only known to be associated with the highly structured and — highly variable streamer belt. There is growing evidence from multiple-station intensity scintillation measurements of solar wind velocity — usually referred to as IPS for interplanetary scintillation— that the slow wind originates in localized regions of the solar corona overlying the streamer belt. In this paper, velocity structure in the corona is investigated based on velocities deduced from the power spectra of single-station intensity scintillation measurements carried out by Voyager 2 during its solar conjunctions in 1979 and 1982 using its Sand X-band (13 and 3.6 cm wavelengths, respectively) radio signals. As in previous IPS studies, low speed wind is observed. Unlike previous studies of the inner corona, simultaneous estimates of density fluctuation from the same intensity scintillation measurements are available to provide the context for the Voyager 2 velocity measurements. Prominent enhancements in density fluctuation characterizing streamer stalks are found to coincide with the low speed wind, leading to the first observational evidence that streamer stalks are the long sought sources of the slow solar wind.