Heliographic latitude dependence of the dominant polarity of the interplanetary magnetic field by comparison of simultaneous Pioneer 10 and Heos 1, 2 data

The heliographic latitude depen- dence of the interplanetary magnetic field was studied by using simultaneous measurements taken with Pioneer l0 at 1.0-4.3 AU and with earth satellites Heos i and 2 at 1.0 AU during Bartels solar rotations (SR) 1896-1913. The results indicate that the greater the difference in heliographic latitude between spacecraft, the greater, on the average, is the observed difference in percentage positive polarity (fields pointing outward from the sun) per SR. In particular, the percentage of positive polarity is greater as the heliographic latitude is more northern. This result is consistent with earlier (1962-1968) evidence of the lati- tude dependence of dominant polarity, provided the phase shift of the dominant polarity sinu- soid, which occurred between 1969 and 1972, is taken into account.