Solar Source of Interplanetary Magnetic Fields

ONE of us (A. S.) 1 has obtained measurements of the mean magnetic field of the Sun (seen as a star) for the period March–June 1968, and has pointed out that a close correlation of this solar field with the sector structure of the interplanetary magnetic field should be expected if the solar–interplanetary correlation described previously 2 existed at the time of his observations. A. S.'s observations give the mean longitudinal magnetic field of the whole solar disk, with the distribution of brightness over the image as a weighting function.