Element and isotopic fractionation in closed magnetic structures

Recent papers have suggested that the slow solar wind is a super-position o f material which is released by reconnection from large coronal loops. This reconnection process is driven by large-scale motions of solar magnetic fl ux driven by the non-radial expansion of the solar wind from the differenti ally rotating photosphere into more rigidly rotating coronal holes. The elemental composition of the slow solar wind material is observed to be fractionated and more variable than the fast solar wind from coronal holes . Recently, it has also been reported that fractionation also occurs in He- 3/He-4. This may be interpreted in the frame-work of an existing model for fractionation on large coronal loops in which wave-particle interactions pr eferentially heat ions thereby modifying their scale-heights.