Uniformity of Longitudinal Distribution of Coronal Mass Ejections

It was found that the heliographic longitudinal distribution of the occurrence of coronal mass ejections (CMEs) was not uniform around the solar minimum of cycle 21. This is confirmed by using the χ2 test for goodness of fit. Sunspot groups and flares show similar non-uniform distributions during the same period. This suggests that there was a longitudinal range where both large-scale and small-scale solar magnetic activities were very low around the solar minimum of cycle 21. The longitudinal range with low activity was more than 150 degrees and continued for approximately four rotations. As solar activity increased, CMEs occurred almost uniformly in heliographic longitude.