2 TYPES OF SLOW SOLAR-WIND

Slow solar wind is associated with rapidly diverging magnetic field occurring (1) at the boundaries of the large polar holes and (2) above small coronal holes. Coronal energy balance models are developed for these two types of sources. We find that the ''reconvergence'' of flux tubes at the polar hole boundaries can explain the high mass flux density of the slow wind near the heliospheric current sheet. However, to account for the high-density wind originating from the small holes prevalent at sunspot maximum, substantially enhanced rates of coronal heating are required.