Electromagnetic pulse

Electromagnetic Pulse, or EMP is the electromagnetic radiation from an explosion (especially a nuclear explosion) or an intensely fluctuating magnetic field caused by Compton-recoil electrons and photoelectrons from photons scattered in the materials of the electronic or explosive device or in a surrounding medium. The resulting electric and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges.The effects are usually not noticeable beyond the blast radius unless the device is nuclear or specifically designed to produce an electromagnetic shockwave. An alternate definition is: a broadband, high-intensity, short-duration burst of electromagnetic energy.

The worst of an electromagnetic pulse generally only lasts for a second, but any unprotected electrical equipment will be affected by the pulse.

EMP is mentioned several times in the Halo Universe:
 * The Power Drainer uses EMP to disable shields and other power sources.
 * The Deep-Space Artifact let out an enormous EM pulse that briefly canceled out all communications in the Sol System. It later let out another pulse upon deactivation.
 * The detonation of Shiva-class Nuclear Warheads are almost always followed by a massive EM pulse.

There is also a scientific inaccuracy regarding EMP. See List of Scientific Inaccuracies in Halo.