text: Chapter 2
  * Electromagnetic jamming.
  * Electromagnetic probing.
  * Meaconing.
  Directed Energy
  2-28. Directed energy is an umbrella term covering technologies that relate to the production of a beam of
  concentrated electromagnetic energy or atomic or subatomic particles. (JP 3-85). Directed energy becomes a
  directed energy weapon when used to conduct EA. A directed-energy weapon is a weapon or system that
  uses directed energy to incapacitate, damage, or destroy enemy equipment, facilities, and/or personnel (JP 3-
  85). EA involving the use of directed-energy weapons is called directed-energy warfare. Directed-energy
  warfare is military action involving the use of directed-energy weapons, devices, and countermeasures (JP
  3-85). The purpose of directed-energy warfare is to disable, cause direct damage, or destroy enemy
  equipment, facilities, or personnel. Another use for directed-energy warfare is to determine, exploit, reduce,
  or prevent hostile use of the EMS by neutralization or destruction.
  Electromagnetic Pulse
  2-29. Electromagnetic pulse is a strong burst of electromagnetic radiation caused by a nuclear explosion,
  energy weapon, or by natural phenomenon, that may couple with electrical or electronic systems to produce
  damaging current and voltage surges (JP 3-85). The effects of an electromagnetic pulse can extend hundreds
  of kilometers depending on the height and power output of the electromagnetic pulse burst. A high-altitude
  electromagnetic pulse can generate destructive effects over a continent-sized area. The most affected portion
  of the EMS by electromagnetic pulse or high-altitude electromagnetic pulse is the radio spectrum.
  Electromagnetic energy produced by an electromagnetic pulse excludes the highest frequencies of the optical
  (infrared, visible, ultraviolet) and ionizing (X and gamma rays) ranges. An indirect impact of an
  electromagnetic pulse or high-altitude electromagnetic pulse includes electrical fires caused by the
  overheating of electrical systems and components.
  Reactive Countermeasures
  2-30. EA includes reactive countermeasures as a response to an enemy attack in the EMS. Response to
  enemy attack may include employing radio frequency countermeasures, such as flares and chaff, in disrupting
  enemy systems and weapons, such as precision-guided or radio-controlled weapons, communications
  equipment, and sensor systems. Radio frequency countermeasures are any device or technique employing
  radio frequency materials or technology that is intended to impair the effectiveness of enemy activity,
  particularly with respect to precision guided and sensor systems (JP 3-85). Chaff is radar confusion reflectors,
  consisting of thin, narrow metallic strips of various lengths and frequency responses, which are used to reflect
  echoes for confusion purposes (JP 3-85). Reactive countermeasures may provoke the employment of directed
  energy weaponry or electromagnetic pulse and can include the use of lethal fires. Army forces can disrupt
  enemy guided weapons and sensor systems by deploying passive and active electro-optical-infrared
  countermeasures that include—
  * Smokes.
  * Aerosols.
  * Signature suppressants.
  * Decoys.
  * Pyrotechnics.
  * Pyrophoric.
  * Laser jammers.
  * High-energy lasers
  * Directed infrared energy.