  This paper primarily considers the potential effects of a single
high-altitude nuclear burst on the U.S. power grid. A comparison is made
between EMP and natural phenomena such as lightning. This paper concludes that
EMP is no more harmful to the power grid than its counterparts in nature. An
upper limit of the electric field of the very fast, high-amplitude EMP is
derived from first principles. The resulting values are significantly lower
than the commonly presented values. Additional calculations show that the
ionization produced by a nuclear burst severely attenuates the EMP.
