DEFINITION OF EMP
There are already many excellent definitions of EMP available on the web. We have provided three, which follow, that we believe offer an accurate, basic level explanation of electromagnetic pulse.
CONGRESSIONAL RESEARCH SERVICE
“Electromagnetic Pulse (EMP) is an instantaneous, intense energy field that can overload or disrupt at a distance numerous electrical systems and high technology microcircuits, which are especially sensitive to power surges. A large scale EMP effect can be produced by a single nuclear explosion detonated high in the atmosphere. This method is referred to as High-Altitude EMP (HEMP). A similar, smaller-scale EMP effect can be created using non-nuclear devices with powerful batteries or reactive chemicals. This method is called High Power Microwave (HPM). Several nations, including reported sponsors of terrorism, may currently have a capability to use EMP as a weapon for cyber warfare or cyber terrorism to disrupt communications and other parts of the U.S. critical infrastructure. Also, some equipment and weapons used by the U.S. military may be vulnerable to the effects of EMP.”
Source: CRS Report for Congress
INSTITUTE FOR TELECOMMUNICATION SCIENCES
“electromagnetic pulse (EMP): 1. The electromagnetic radiation from a nuclear explosion caused by Compton-recoil electrons and photoelectrons from photons scattered in the materials of the nuclear 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. May also be caused by nonnuclear means. [JP1] 2. A broadband, high-intensity, short-duration burst of electromagnetic energy. (188) Note: In the case of a nuclear detonation, the electromagnetic pulse consists of a continuous frequency spectrum. Most of the energy is distributed throughout the lower frequencies between 3 Hz and 30 kHz.”
Source: ITCS, research and engineering branch of the National Telecommunications and Information Administration (NTIA), a part of the U.S. Department of Commerce (DOC).
“Electromagnetic pulse The term electromagnetic pulse (sometimes abbreviated EMP) has the following meanings: A burst of electromagnetic radiation from an explosion (especially a nuclear explosion) or a suddenly fluctuating magnetic field. The resulting electric and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges. For a comprehensive assessment of likely damages to electronics equipment and electrical infrastructure, see the 2008 Critical National Infrastructures Report written by the EMP Commission of the U.S federal government. A broadband, high-intensity, short-duration burst of electromagnetic energy.”
Source: Wikipedia, Electromagnetic Pulse