Statistic study on the geomagnetic storm effectiveness of solar and interplanetary events Original Research Article

In the literature on the solar–terrestrial relations there are different estimations of storm effectiveness of solar and interplanetary events – from 30% up to 100%. We made a review of published results and found that different results arise due to differences in the methods used to analyze the data: (1) the directions in which the events are compared, (2) the pairs of compared events, and (3) the methods of the event classifications. We selected papers using: (1) the analysis on direct and back tracings of events, and (2) solar (coronal flares and CMEs), interplanetary (magnetic clouds, ejecta and CIR) and geomagnetic disturbances (storms on Dst and Kp indices). The classifications of magnetic storms by the Kp and Dst indices, the solar flare classifications by optical and X-ray observations, and the classifications of different geoeffective interplanetary events are compared and discussed. Taking into account this selection, all published results on the geoeffectiveness agree to each other in each subset: “CME → Storm” (40–50%), “CME → MC, Ejecta” (60–80%), “MC, Ejecta → Storm” (50–80%), “Storm → MC, Ejecta” (30–70%), “MC, Ejecta → CME” (50–80%), “Storm → CME” (80–100%), “Flare → Storm” (30–40%) and “Storm → Flare” (50–80%).