Travel time classification of extreme solar events: Two families and an outlier

Abstract

AbstractExtreme solar events are of great interest because of the extensive damage that could be experienced by technological systems such as electrical transformers during such periods. In studying geophysical phenomena, it is helpful to have a quantitative measure of event strength so that similar events can be intercompared. Such a measure also allows the calculation of the occurrence rates of events with varying strength. We use historical fast travel time solar events to develop a measure of strength based on the Sun‐Earth trip time. We find that these fast events can be grouped into two distinct families with one even faster outlier. That outlier is not the Carrington event of 1859 but the extremely intense solar particle event of August 1972.