Reduction and analysis of magnetometer data from Mariners 4 and 5

In studies of data from the Mariner 4 and Mariner 5 magnetometers evidence has been found that during the flights, negative (toward the sun) polarity dominated at latitudes above the solar equatorial plane and positive polarity dominated at latitudes below this plane. A subsequent check of data taken with other spacecraft during 1964 through 1967 provided additional evidence of this effect. It is suggested that the dominant polarity of the interplanetary magnetic field follows the hemisphere-dependent dipolar field of the sun. Thus, the photospheric dipolar field may be an important source of the interplanetary magnetic field, especially at quiet times. It has also been found that, for an interplanetary magnetic field of a given polarity, the north-south component has a nonzero mean value in regions above and below the solar equatorial plane.