The relation between aurorae and coronal holes

In this paper we analyze the relation between the evolution of polar and low latitude coronal holes area and the annual number of aurorae at invariant latitudes ≤620 during sunspot cycles 20 and 21. We found that the number of aurorae is well and positively correlated with polar coronal holes size when they are large enough to reach solar latitudes below 600, and negative when they are smaller. During the later period, the frequency of aurorae correlates well and positively with the evolution of low latitude holes which appear at the Sun between ±600