The spiral interplanetary magnetic field: a polarity and sunspot cycle variation.

Spacecraft observations near the earth of the average direction of the interplanetary magnetic field during the sunspot maximum year 1968 showed a deviation from the spiral field of Parker's classical description. The included angle between the average field direction when the field polarity was away from the sun and the average direction when the field polarity was toward the sun was 168 degrees , rather than 180 degrees as predicted by Parker. This effect appears to have a sunspot cycle variation.