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

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 degrees S latitude. Thus we find evidence that the wind flow near 25 degrees S comes from a region poleward of 60 degrees S, consistent with magnetic field models.