A solar cycle variation of the interplanetary magnetic field configuration

The representation of the sector boundaries, published by Svalgaard (1974, 1975) in a superposed 27-days Bartels format showed that they have a significant preference to occur in certain days of the solar rotation. Further study of these data, as well as of the polarized days in the vicinity of them, pointed out that during the epoch of extrema of the 11-year cycle there is a well-established 2-sector structure, on the average. On the contrary, a mean 4-sector structure is more prominent during the intermediate years.