Wiktionary
n. 1 A short-duration burst of high-intensity electromagnetic radiation generated by a physical event, in particular by a large thermonuclear explosion in the atmosphere. The pulse causes a damaging surge of voltage within electrical and electronic systems. 2 http://en.wikipedia.org/wiki/Compton%20scattering electrons and photoelectrons from photons scattered in the materials of a nuclear event causing electric and magnetic fields to couple with electrical and electronic systems to produce damaging current surges.
Wikipedia
An electromagnetic pulse (EMP), also sometimes called a transient electromagnetic disturbance, is a short burst of electromagnetic energy. Such a pulse's origination may be a natural occurrence or man-made and can occur as a radiated, electric or magnetic field or a conducted electric current, depending on the source.
EMP interference is generally disruptive or damaging to electronic equipment, and at higher energy levels a powerful EMP event such as a lightning strike can damage physical objects such as buildings and aircraft structures. The management of EMP effects is an important branch of electromagnetic compatibility (EMC) engineering.
Weapons have been developed to create the damaging effects of high-energy EMP. These are typically divided into nuclear and non-nuclear devices. Such weapons, both real and fictional, have become known to the public by means of popular culture.
Usage examples of "electromagnetic pulse".
The real problem was that Jake could only survive if he was shielded against electromagnetic pulse, which meant one of five places: Ops, the central axis of DS9, or one of the three phaser-fire control rooms between the top and bottom weapons sails.
The effects of the electromagnetic pulse had subsided, so Sanusi could maintain radio contact with his men while taking a closer look at Mersa Matruh.
They had bombs doped with elements that might interfere with the magnetic filaments, perhaps producing an electromagnetic pulse to scramble the field lines' snarls, lowering their information-bearing capacity.
The electromagnetic pulse created just before impact was detected by our early warning and nuclear detonation satellite system, which accurately measured it.
Instead of building a continuous shield structure, we have to detect each separate group and divert it away from Earth with an electromagnetic pulse generated for just that bundle.
The EMP--electromagnetic pulse--was far more destructive to the ships in the vicinity than the relatively small blast effect the missile produced.
Had any of it been placed in a medium unaffected by the electromagnetic pulse?
A nuclear detonation in space might, from EMP effects - that's electromagnetic pulse.