Natural Sources of EMP
EMP Caused by Geomagnetic Storm
Geomagnetic storms occur regularly and usually have effects at high northern latitudes however major storms have inflicted significant damage as in Canada in the 1980’s. A great geomagnetic storm, such as the 1859 Carrington effect, would have catastrophic consequences as the infrastructure has become more sensitive. It is widely believed that great storms are likely to occur every 100 years.

Occasionally plasma erupts from the surface of the sun which is a mass of moving, energy charged plasma. Solar flares or holes in the solar corona can also lead to emissions of an energy wave. The eruption travels through space as a solar wind and if aligned toward the earth the solar wind shock wave can hit the earth’s atmosphere which has magnetic properties. The shock typically occurs 24 to 36 hours after a solar event and magnetic storms usually last for 1 to 2 days but can last for many days. The solar wind will have a magnetic property or bursts of energy that can, in a large geomagnetic storm, rapidly change the magnetic field around the earth’s core leading to induced currents of energy in long metallic conductors (wires, rails, etc.). Transformers in the Grid used to step up or step down power voltages are connected to these wires and are subject to damage in the cores where wire copper windings can melt from the induction strong of strong magnetic fields in the transformers from the increased current in the wires caused by EMP. There are some 300 key transformers that are used in the initial segments of the U.S. Electric Grid. There are few spares and replacement manufacture can take over a year under normal conditions. Considering that these units are not manufactured in the U.S. replacements could take much longer to obtain, if ever.