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.