Magnetospheric Storms and Substorms

Abstract

Strongly perturbed conditions in the magnetosphere form a class of phenomena that we call magnetospheric storms. Historically, they have been observed as strong perturbations of the Earth’s magnetic field, and thus they are often referred to as magnetic storms. Storms are truly global and can be seen in magnetic recordings all over the Earth. During a magnetic storm a number of more localized substorms may take place. Despite their suggestive name substorms should not be seen just as building blocks of storms. A storm is more than the sum of substorms. On the other hand, isolated substorms, i.e., non-storm-time substorms, are actually much more common than substorms occurring during strong magnetospheric perturbations.