Evidence for a high‐latitude origin of lower latitude high‐speed wind

Abstract

Using low‐frequency spectra of the wind speed, density, and magnetic field strength, we show that the near‐streamer belt solar wind at solar minimum exhibits many harmonics of fundamental frequencies corresponding to 26‐ and 34‐day periods. Nearly all the low‐frequency peaks in the spectra can be explained by these harmonics. The 26‐day period is that of coronal hole rotation, and the 34‐day period is naturally associated with the photospheric rotation period at about 70° S latitude. Thus we find evidence that the wind flow near 25° S comes from a region poleward of 60° S, consistent with magnetic field models.