From the thesis abstract: "The detonation of a single nuclear weapon at a high altitude above the United States, or a major solar geomagnetic storm, would create electromagnetic pulses which have the potential to catastrophically impact the survivability of the United States. The electrical power grid is fragile, and is extremely vulnerable to an electromagnetic pulse. Its failure would result in the loss of almost all logistical functions necessary to support our modern society. This paper will examine the causes, threats, probable effects, and what measures can be taken to mitigate the potential impact to the Homeland."
Defense Technical Information Center (DTIC): http://www.dtic.mil/dtic/