The height of solar wind origin in coronal funnels and a 3-D scenario for solar wind formation

The height of the solar wind origin in coronal funnels is fixed by a comparison and correlation between the coronal magnetic field, constructed by force-free extrapolation from the photospheric magnetic field measured by MDI, and the radiance and Doppler maps of EUV radiation lines observed by SUMER on SOHO. Empirically, this height should be larger than 5 Mm, since here the CIV intensity has a maximal correlation coefficient with the extrapolated field strength and CIV does not have significant Doppler shifts in coronal funnels. The height clearly must be lower than 20 Mm, where large blue shifts of NeVIII are found, thus indicating outflow in coronal funnels. Based on these correlations between the ultraviolet emission and the extrapolated magnetic field, a new 3-D formation scenario of the solar wind is suggested. The flow starts at a height of about 5 Mm and the plasma subsequently experiences acceleration and heating in the funnels. However, it is supplied from loops by the side of the funnels through magnetic reconnection driven by supergranulation. The original heating of the solar wind may take place in these side loops.