One of the critical grand challenges of Solar and Space Physics today is understanding and predicting stormtime geospace spanning altitudes from a few tens to millions of kilometers.
The term "geomagnetic storms", coined by Alexander von Humboldt, originates from 19th century observations of sunspots (most notably by Richard Carrington) coinciding with strong perturbations of the geomagnetic field and displays of aurorae. Geomagnetic storms are a consequence of complex plasma disturbances that start at the surface of the sun and then propagate through, and interact with, the interplanetary space environment, before impacting Earth. Storms occur in near-Earth space in response to this increased energy input from the solar wind, especially when coupled with certain interplanetary magnetic field orientations. Storms can have different solar and interplanetary drivers but intense and extreme events often involve series of coronal mass ejections (CMEs) or composites of structures including CMEs and corotating interaction regions.
Stormtime geospace is a system of systems representing interconnected physical domains of the near-Earth environment: the magnetosphere, including all of its regions; the ionosphere; the upper atmosphere in which the ionosphere is embedded. Geospace is driven by disturbances at its outer boundary and interacts with the lower atmosphere at low altitudes. The different domains of geospace are populated by neutral gases and plasmas that are immersed in electromagnetic fields and evolve on disparate temporal and spatial scales. During storms, all of these domains become active and engage in complex, cross-scale interactions that profoundly alter the entire system. The complexity of the underlying physical processes defines the daunting challenge of predicting the most severe impacts of space weather on our technological infrastructure.
To highlight their pervasive effects throughout geospace, we refer to geomagnetic storms as geospace storms.