The present acceptance of the existence of varying substorm sizes was not always so. The 1978 Victoria conference on the definition of substorms refused to consider size as an important issue in substorms. In fact, the author distinctly remembers one very senior scientist stating flatly that substorms did not have different sizes. This statement is true in a technical sense because there is no accepted measure of the size of a substorm despite over 30 years of research on substorms. Atmospheric storms and hurricanes have a measure of size based on the strength of their winds.
Earthquakes have measures of size depending on either the destruction caused or the energy released.
Solar flares have measures of size for each of several wavelengths but substorms have no measure of strength. Plots of AE are generally now shown, but the AE index is not a good measure when the substorm is small and is poleward of the usual longitudinal AE chain of stations or if it is large and equatorward of the AE chain. Also, the AE chain is very uneven in its longitudinal coverage. Thus, researchers seem to have shied away from quantifying substorms by their peak AE response. Substorm researchers do not talk about a 500 nT substorm, a 1000 nT substorm, etc.