On the possible association of coronal hole dynamics with coronal mass eruptions and major geomagnetic storms Original Research Article

It is shown that magnetic Storm Sudden Commencements (SSC) can be preceded by the following effects in the dynamics of coronal holes (CH): (1) changes in the configuration of neighbouring CHs which shows up as a decrease in the distance between the boundaries (or portions of the boundaries) of two CHs, and as the subsequent restoration of these boundaries to a state similar to the original state; (2) the appearance of a new transient or long-lived CH. These effects reveal themselves most vividly in ≈ 41% of the events under consideration. It is concluded that these effects in the dynamics of coronal holes are an indication of the fact that a coronal mass eruption has occurred. It is shown that events with a clearly defined effect in the CH dynamics are associated with the strongest magnetic storms. For 80% of such events the storm amplitude maxKp > 5o, and the mean value of the storm intensity 〈maxKp〉 = 7o.