Electromagnetic pulse

Electromagnetic pulse (EMP) is a phenomenon, usually associated with the explosion of a nuclear weapon but also by the operation of specialized generators driven by conventional explosives, which produces radiation in the radiofrequency and lower-frequency electrical bands. The pulse produced by this phenomenon may damage or destroy electrical or electronic components. Note that ionizing radiation from nuclear explosions also can directly damage solid-state electronic components, but by a different mechanism than EMP.

The best-known scenario for large-scale damage by EMP involves the explosion of a high-yield nuclear weapon at a very high altitude.

Characteristics of EMP
Vulnerability has two components:
 * Coupling modes possible between the EMP source and the equipment
 * Front door coupling goes through an antenna intended to receive power in the frequency range being generated
 * Back door coupling in which the EMP produces surges in power (including ground) and communications wire.
 * The level of energy coupled that will damage or destroy a particular target.

Generating EMP
While EMP often is assumed to be a characteristic of nuclear weapons alone, such is not the case. . Several open-literature techniques, requiring only conventional explosives, or, in the case of high power microwave, a large electrical power supply, perhaps one-shot as with capacitors, can generate a significant EMP:
 * Explosively pumped flux compression generators (FCG)
 * Explosive and Propellant Driven MHD Generators
 * High Power Microwave Sources - Spark gaps or the Vircator