VERTICAL FIBRIL STRUCTURE WITHIN SOLAR PROMINENCES

Recent observations have shown that, rather than being uniform blocks or clouds of cool material, solar prominences contain a great amount o f fine structure in three dimensions. This model builds on a previous model allowing variations in the two horizontal directions but now int roduces variation in the vertical direction. The resulting prominence, therefore, consists of a number of cool threads occupying dips in the magnetic field. However, these cool fibrils are of differing vertical extents i.e. some survive across a region of transition where the pro minence geometry changes with height, while others exist only above or below such a region. At the upper or lower edge of a fibril, the vert ical extent of the dip is negatively correlated with the temperature i .e. as the dip evens out, the temperature returns to coronal values. N either the thermal nor the magnetic structure in the corona around the prominence is influenced by the fibril structure within the prominenc e.