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An electromagnetic pulse is a short surge of electromagnetic energy. Its short duration means that it will be spread over a range of frequencies. Pulses are typically characterized by: The mode of energy transfer (radiated, electric, magnetic or conducted). The range or spectrum of frequencies present. Pulse waveform: shape, duration and amplitude.
Macroscopically, Maxwell's equations show that in the absence of free charges and currents an electromagnetic field interacts with matter via the optical polarization .The wave equation for the electric field reads () (,) = (,) and shows that the second derivative with respect to time of , i.e., , appears as a source term in the wave equation for the electric field .
The electromagnetic spectrum portion of the information environment is referred to as the electromagnetic environment (EME). The recognized need for military forces to have unimpeded access to and use of the electromagnetic environment creates vulnerabilities and opportunities for electronic warfare in support of military operations.
E. Earth–ionosphere waveguide; Elastance; Electric field; Electric-field integral equation; Electricity and Magnetism (book) Electromagnet; Electromagnetic brake
A nuclear electromagnetic pulse (nuclear EMP or NEMP) is a burst of electromagnetic radiation created by a nuclear explosion. The resulting rapidly varying electric and magnetic fields may couple with electrical and electronic systems to produce damaging current and voltage surges .
Devices being characterized could include radars, communication radios, radio signals from foreign remote sensors, radio frequency weapons (RFW), collateral signals from other weapons, weapon precursors, or weapon simulators (for example, electromagnetic pulse signals associated with nuclear bursts); and spurious or unintentional signals.
Electromagnetic environment; Electromagnetic forming; Electromagnetic pulse; Nuclear electromagnetic pulse; Electromagnetic reverberation chamber; Electromagnetic shielding; Electromagnetic wave equation; Emission spectrum; Epirus Leonidas; Equivalence of direct radiation; Euler–Heisenberg Lagrangian
In this example there are 1000 pulses per second (one kilohertz pulse rate) with a gated pulse width of 42 μs. The pulse packet frequency in this example is 27.125 MHz of RF energy. The duty cycle for a pulsed radio frequency is the percent time the RF packet is on, 4.2% for this example ([0.042 ms × 1000 pulses divided by 1000 ms/s] × 100).