|There is more information available on this subject at Electromagnetic pulse on the English Wikipedia.|
An electromagnetic pulse (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 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.
EMP is mentioned several times in the Halo Universe:
- In the level Two Betrayals in Halo: Combat Evolved, Cortana converts John-117's energy shields into an EMP to disable Halo's Phase Pulse Generators.
- The detonation of Shiva-class Nuclear Missiles are followed by a massive electromagnetic pulse.
- The Deep-Space Artifact released an enormous electromagnetic pulse that briefly disabled all communications in the Sol System.
- In Halo: First Strike, John-117 used a Plasma Grenade's EMP charge to disable the electronics of a locked door on Ascendant Justice. This allowed him to open the door.
- The in-atmosphere jumping of the Prophet of Regret's assault carrier to slipspace above New Mombasa created a massive electromagnetic pulse that damaged electrical systems in the city.
- A charged Plasma Pistol blast will completely deplete energy shields.
- In Halo: Combat Evolved, a plasma grenade explosion can completely deplete energy shields.
- In all Halo games except Halo: Combat Evolved, a charged Plasma Pistol blast will temporarily disable vehicles.
- In Halo 2, the Sentinels emit an EMP that completely depletes shields when destroyed.
- In Halo 3, the Power Drain uses EMP to disable shields, vehicles and other power sources.
- In Halo Wars, Professor Anders' vehicle, the Gremlin, uses EMP as main armament to disable enemy non-infantry units.
- In Halo Wars, the Vampire's Stasis Drain Cannon uses EMP to drain power from enemy aircraft.
- In Halo: Reach, the M319 Individual Grenade Launcher's grenades release an EMP when detonated.
- In Halo: Reach, an EMP is released when the player comes out of Armor Lock.
- In Halo: Reach, the Covenant Spires in the Battle of Viery possessed a protective electromagnetic shield to disable enemy vehicles.
- A vehicle disabled by an EMP will still have full functionality of its weapons if it has any. For example, if a Warthog is disabled by an EMP, the turret will still be able to turn around and shoot.