The Role of Substorms in Influencing Types of Space Weather That Have Damaging Consequences

Gordon Rostoker

University of Alberta

After first providing a modern definition of a substorm, this talk will deal with the role reconnection in the magnetotail plays in providing the energy that is required for expansion phase activity. How the storm time ring current develops will follow as a natural consequence of the substorm definition. In terms of space weather consequences, it will be emphasized that a large portion of the energy provided through reconnection is of no consequence for disruption of technological systems in space or on the ground. What is of consequence is rate of change of the electromagnetic field, either through short term rapid changes associated with substorms or through longer term ULF and/or VLF variations. A technique will be outlined which can be applied to the prediction of the large rate of change of magnetic field which characterizes substorm expansion phase activity The talk will conclude by addressing the conditions required for the appearance of enhanced relativistic electron fluxes at geostationary orbit, and how those conditions might be predicted.