GLOSSARY E

E-MAIL BOMB - An automated script which generates a chain of e-mail messages intended to overload the resources of the victim server processor, or Mail Transfer Agent (MTA). [10:2862] Also called DENIAL OF SERVICE (DOS) ATTACK. NOTE: E-mail bombs include chain bombs, error-message bombs, covert distribution, and mail exploder exploitation, among other techniques.

EARLY WARNING AND CONTROL SYSTEM (EWCS) - A ballistic defense radar system that can maintain constant surveillance of the threat horizon and rapidly detect ballistic missiles at launch distances of more than 1,500 kilometers (930 miles), automatically initiating and maintaining target tracking. It produces a high-resolution image of targets down to less thatn 1 meter is size, facilitating identification of the threat and discrimination of the warhead. Jam resistant, the EWACS can track multiple threats simultaneously while maintaining full surveillance. In addition, radar data identifies the launch point, predicts the flight track and evaluates the impact point. [10:2783]

EARTHING - The process of making a satisfactory electrical connection between the structure, including metal skin, of an object or vehicle, and the mass of the earth, to insure a common potential with the earth. [1] See also BONDING, GROUNDING.

ECHELON - An intelligence global surveillance network for intercepting and processing the world's communications using numerous satellites, microwave listening stations and subsurface assets. []

ECHO - In radar, the portion of energy of the transmitted pulse that is reflected to a receiver. [3] See also RADAR ECHO.

ECM INTERROGATION - The use of RF transmissions that closely simulate friendly weapons system RF transmissions in order to generate adversary ECM responses. [10:36] NOTE: Information from ECM interrogation is used by designers of ECCM systems.

EDGE TRACKING - An ECCM technique which uses only the leading (or trailing) edge of the target pulse for range tracking. [8]

EFFECTIVE DAMAGE - That damage necessary to render a target element inoperative, unserviceable, nonproductive, or uninhabitable. [1]

EFFECTIVE RADIATED POWER (ERP) - In a given direction, the relative gain of a transmitting antenna with respect to the maximum directivity of a half-wave dipole multiplied by the net power accepted by the antenna from the connected transmitter. [3]

EFFECTS BASED OPERATIONS (EBO) - The use of advanced technologies to help understand the enemy as a "system of systems." [10:2901] NOTE: Effects based operations involves the examination of an adversary's military might as well as political, economic, cultural and decision-making factors in order to find weaknesses that can be exploited to defeat an enemy's ability to make war.

EJECTION INTERVAL - The time between the dispensing of individual decoys within a salvo or burst. [] Contrast with SALVO INTERVAL.

ELASTOMER - A silicon strip of alternating conductors and insulators used in printed circuit boards. []

ELECTRICAL MATERIALS - That category of MATERIALS TECHNOLOGY which addresses superconducting electrical materials that provide the capability for lightweight, compact, high-power motors, magnets, and energy storage systems. [12]

ELECTRICAL STUN DEVICE - A NONLETHAL WEAPON which stuns target individuals with a high voltage, very low current, short duration electric shock that incapacitates the individual. [10:2745]

ELECTRIC ARMOR - A means of protecting an object from projectile collision. SHAPE MEMORY ALLOYS (SMA) are heated with pulsed electrical power at the instant of collision, augmenting the effective thickness of the shield, thereby increasing its resistance to penetration. [] See also ELECTROMAGNETIC ARMOR. NOTE: NASA is considering using electric armor to shield the new International Space Station from potentially dangerous collisions with space debris.

ELECTRODYNAMIC TETHER - A space-based current-carrying wire that harnesses the Earth's magnetic field to provide propulsive force. [10:2835]

ELECTROEXPLOSIVE DEVICE (EED) - Tiny explosive charges used to trigger weapon systems, ejection seats, or to jettison bombs and fuel tanks. []

ELECTROLUMINESCENCE - (1) The emission of light from a phosphor excited by an electromagnetic field. (2) Nonthermal conversion of electrical energy into light, such as in a light-emitting diode. [3*]

ELECTROLUMINESCENT (EL) DISPLAY - An optoelectronic device with a multiplicity of electric ports, each capable of independently producing an optic output from an associated electroluminator element. [3]

ELECTROMAGNETIC AIRCRAFT LAUNCHING SYSTEM (EMALS) - An electrically-powered catapult system intended to replace the steam-powered catapult. [10:2697] NOTE: Although EMALS will require increased electrical capacity in aircraft carriers, the system will increase safety by eliminating steam lines, and reducing weight, maintenance, and personnel requirements.

ELECTROMAGNETIC ARMOR - A form of ACTIVE ARMOR that is an application of SMART ARMOR which which offers protection as follows: (1) The penetrating jet of a shaped charge (SC) is detected; (2) an intense electrical discharge is created between electrically conductive plates, creating a powerful magnetic field; (3) the magnetic field interacts with the charged particles of the penetrating jet; and (4) magnetohydrodynamic instabilities occur, disrupting the jet. [10:2719] See also ELECTRIC ARMOR, REACTIVE ARMOR.

ELECTROMAGNETIC COMPATIBILITY (EMC) - (1) The ability of a device to function satisfactorily in its ELECTROMAGNETIC ENVIRONMENT without introducing intolerable disturbance to that environment (or to other devices). [3] (2) The ability of systems, equipment, and devices that utilize the electromagnetic spectrum to operate in their intended operational environments without suffering unacceptable degradation or causing unintentional degradation of electromagnetic radiation or response. It involves the application of sound electromagnetic spectrum management; system, equipment, and device design configuration that ensures interference-free operation; and clear concepts and doctrines that maximize operational effectiveness. [7:CJCS MOP 6, APPENDIX B]

ELECTROMAGNETIC DECEPTION - The deliberate radiation, re-radiation, alteration, suppression, absorption, denial, enhancement, or reflection of electromagnetic energy in a manner intended to convey misleading information to an enemy or to enemy electromagnetic-dependent weapons, thereby degrading or neutralizing the enemy's combat capability. Among the types of electromagnetic deception are: a. Manipulative Electromagnetic Deception -- Actions to eliminate revealing, or convey misleading, electromagnetic telltale indicators that may be used by hostile forces. b. Simulative Electromagnetic Deception -- Actions to simulate friendly, notional, or actual capabilities to mislead hostile forces. c. Imitative Electromagnetic Deception -- The introduction of electromagnetic energy into enemy systems that imitates enemy emissions. [7:CJCS MOP 6, APPENDIX B]

ELECTROMAGNETIC ENVIRONMENT ALLOCATION - The process of assigning spectral regions to sensors, active radiation devices, and reflectors in order to regulate emissions, minimize mutual interference, and carry out the force EMISSION CONTROL (EMCON) plan. []

ELECTROMAGNETIC INDUCTION DETECTOR - A fast-response device used to locate mines and other metallic objects by determining the time constant rate of decay of induced electromagnetic radiation. []

ELECTROMAGNETIC INTERFERENCE (EMI) - Any electromagnetic disturbance that interrupts, obstructs, or otherwise degrades or limits the effective performance of electronics/electrical equipment. It can be induced intentionally, as in some forms of electronic warfare, or unintentionally, as a result of spurious emissions and responses, intermodulation products, and the like. [1]

ELECTROMAGNETIC INTERFERENCE (EMI) GASKET - A monel mesh gasket, impregnated with silicone gel, to seal a surface on contact and keep the electrolyte away from the metal-to-metal interface, which is otherwise subject to galvanic corrosion due to conductive metal powders used in the gasket. [10:2540]

ELECTROMAGNETIC INTRUSION - The intentional insertion of electromagnetic energy into transmission paths in any manner, with the objective of deceiving operators or of causing confusion. See also INTRUSION. [1]

ELECTROMAGNETIC OBSCURANT - Smoke, dust, mist, and other particular material deliberately generated to degrade the enemy's sensors and deny detailed information about the protected unit(s). [] See also AEROSOL.

ELECTROMAGNETIC PULSE (EMP) - 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 non-nuclear means. [1] Also called NUCLEAR MAGNETIC PULSE (NEMP). See also NEMP COUNTERMEASURES, INDUCED ELECTROMAGNETIC PULSE (IEMP), SYSTEM-GENERATED ELECTROMAGNETIC PULSE (SGEMP). NOTE: A single high-altitude nuclear burst of 10 or more megatons at the geographic center of North America would, within 3 to 5 NANOSECONDS, disable virtually every kind of unprotected electronic and electrical circuit. Damage to crucial weapons control systems could be irreversible within the limited time available to respond. [10:2541]

ELECTROMAGNETIC RADIATION - Radiation made up of oscillating electric and magnetic fields and propagated with the speed of light. Includes gamma radiation, X-rays, ultraviolet, visible, and infrared radiation, and radar and radio waves. [1]

ELECTROMAGNETIC RADIATION HAZARDS (RADHAZ) - Hazards caused by a transmitter / antenna installation that generates ELECTROMAGNETIC RADIATION in the vicinity of ordnance, personnel, or fueling operations in excess of established safe levels or increases the existing levels to a hazardous level. These hazards will exist when an electromagnetic field of sufficient intensity is generated to: a. Induce or otherwise couple currents and/or voltages of magnitudes large enough to initiate electro-explosive devices or other sensitive explosive components of weapon systems, ordnance, or explosive devices. b. Cause harmful or injurious effects to humans and wildlife. c. Create sparks having sufficient magnitude to ignite flammable mixtures of materials that must be handled in the affected areas. [1] Synonymous with EMR Hazards, and HAZARDS OF ELECTROMAGNETIC RADIATION TO PERSONNEL, ORDNANCE, AND VOLATILE MATERIAL (HERO). For additional discussion, click . [11.2]

ELECTROMAGNETIC RADIATION REFLECTION - The abrupt change in direction of an electromagnetic WAVE at an interface between two dissimilar media so that the wave returns into the medium from which it originated. See also SKIN ECHO. [3]

ELECTROMAGNETIC RADIATION SHIELDING - The protection of a device from electromagnetic radiation by an electromagnetic shield. The shield consists of a screen, housing, or other object, usually conducting, that substantially reduces the effect of electric or magnetic fields on one side thereof, upon devices or circuits on the other side. [3]

ELECTROMAGNETIC RADIATION SIGNATURE - (1) As applied to a radar, its specific radiation parameters that may allow it to be distinguished from all others, even of the same type. [8] (2) Radiated signals clearly indicating the system mode of operation, purpose, and to a certain extent the variety of countermeasure action likely to prove most profitable. [10:2] (3) Characteristics associated with an emitter, such as Carrier frequency; Pulse repetition frequency (PRF); Pulse width (PW); Antenna scan rate; Antenna scan pattern; Antenna SIDE LOBE structure; and Message contents (AM, FM, digital, etc.). [10:2]

ELECTROMAGNETIC REFLECTION - Electromagnetic energy diverted back from the interface of two media. The reflection may be specular (i.e., direct) or diffuse according to the nature of the contact surfaces. [1]

ELECTROMAGNETIC SPECTRUM - The range of frequencies of electromagnetic radiation from zero to infinity. Also called FREQUENCY SPECTRUM. It is divided into 11 radio-wave propagation frequency ranges.

RADIO SPECTRUM (radio-wave propagation)
ULF	lower than 3 Hz
ELF	3 Hz - 3 kHz
VLF	3 - 30 kHz
LF	30 - 300 kHz
MF	300 kHz - 3 MHz
HF	3 - 30 MHz
VHF	30 - 300 MHz
UHF	300 MHz - 3 GHz
SHF	3 - 30 GHz
EHF	30 - 300 GHz
Submillimeter	300 GHz - 1 THz
Source [3]

Alternatively, it is divided into 26 alphabetically designated bands. ECM Bands A through M are listed below: [1] NOTE: X-Band radars operate in the range 8-12 GHz.

Band	Low-End Freq (GHz)
A	0.0
B	0.25
C	0.5
D	1
E	2
F	3
G	4
H	6
I	8
J	10
K	20
L	40
M	60

ELECTROMAGNETIC WEAPON - Any device which can produce an electromagnetic field of such intensity that targeted items of electronic equipment experience either a SOFT KILL or a HARD KILL. [10:2824]

ELECTROMAGNETICALLY INDUCED TRANSPARENCY (EIT) - A technique that makes normally opaque substances transparent to light by applying another source of light, such as a laser beam, that interferes with the opaque substance's absorption of light. [10:2882] NOTE: This property was first demonstrated (ca 2000) by Harvard physicist Lene Hau. A pulse of light was stopped, stored briefly within a substance, and then released on command.

ELECTRONIC ATTACK (EA) - That division of ELECTRONIC WARFARE involving the use of electromagnetic or directed energy to attack personnel, facilities, or equipment with the intent of degrading, neutralizing, or destroying enemy combat capability. Electronic Attack includes: (1) Actions taken to prevent or reduce an enemy's effective use of the electromagnetic spectrum, such as jamming and electromagnetic deception; and (2) Employment of weapons that use either electromagnetic or DIRECTED ENERGY (de) as their primary destructive mechanism (LASER, RF weapons, PARTICLE BEAMS). [7:CJCS MOP 6; APPENDIX B] Also called ELECTRONIC COUNTERMEASURES (ECM).

ELECTRONIC CAMERA - A camera which records the image on a floppy diskette. The diskette may then be played back into a video imaging terminal where the recorded image is digitized, compressed and prepared for radio transmission. [10:100]

ELECTRONIC COMBAT (EC) - (1) The ELECTRONIC WARFARE MISSION AREA involving the integrated use of military action to preserve friendly access to the electromagnetic spectrum and to exploit and disrupt enemy military objectives. [4:25] (2) A SPACE AND ELECTRONIC WARFARE (SEW) warfare discipline that targets enemy weapons and weapons systems. It includes the coordination of all measures to provide counter-targeting, counter-weapon, and terminal phase protection to the force. [10:2505] NOTE: Electronic Combat is described as having the core elements "Detect, Disrupt, and Defend". [10:2520]

ELECTRONIC DECEPTION - An electronic countermeasure that is the deliberate radiation, reradiation, alteration, suppression, absorption, denial, enhancement, or reflection of electromagnetic energy in a manner intended to convey misleading information and to deny valid information to an enemy or to enemy electronics-dependent weapons. See also DECEPTION. [1]

ELECTRONIC IMAGERY DISSEMINATION - The transmission of imagery or imagery products by any electronic means. This includes the following four categories: a. primary imagery dissemination system: The equipment and procedures used in the electronic transmission and receipt of unexploited original or near-original quality imagery in NEAR REAL TIME. b. primary imagery dissemination: The electronic transmission and receipt of unexploited original or near-original quality imagery in near-real time through a primary imagery dissemination system. c. secondary imagery dissemination system: The equipment and procedures used in the electronic transmission and receipt of exploited non-original quality imagery and imagery products in other than real or near-real time. d. secondary imagery transmission: The electronic transmission and receipt of exploited non-original quality imagery and imagery products in other than real or near-real time through a secondary imagery dissemination system. [1]

ELECTRONIC INFORMATION SECURITY - Electronic information security is a collection of disciplines which encompass a wide range of applications and environments. These disciplines are tailored to one or more areas of protection, such as COMMUNICATIONS SECURITY (COMSEC), and computer security. Electronic information security involves: cryptography, which consists of encryption and decryption process; keys, which are variables used to periodically change the encryption algorithm so that even if an adversary captures the encrypted information and possesses the algorithm they cannot easily decrypt the information without the key; key distribution, which is the method of placing periodic keys where they are needed (electronically or physically); access control, by which the person attempting electronic access to information is validated as being the person claimed to be (authentication), and the electronic restrictions by which only authorized persons are granted access to specified information; tamper protection, a series of processes, both electronic and physical, established to detect attempts to physically intrude on electronic information or tamper with the security parameters tamper protection also includes protective measures taken in the event of intrusion); and recovery, which is the restoration of operations after a system failure, and includes fail-safe features to prevent information loss or compromise from detectable forms of failure. [10:2564]

ELECTRONIC LINE OF SIGHT - The path traversed by electromagnetic waves that is not subject to reflection or refraction by the atmosphere. [1]

ELECTRONIC MAIL (E-MAIL) - A system whereby a computer user can exchange messages with other computer users (or groups of users) via a communications NETWORK. [10:2736] NOTE: Electronic mail is one of the most popular uses of the Internet.

ELECTRONIC MASKING - The controlled radiation of electromagnetic energy on friendly frequencies in a manner to protect the emissions of friendly communications and electronic systems against enemy ES/SIGINT (electronic warfare support measures/signals intelligence), without significantly degrading the operation of friendly systems. [7:CJCS MOP 6, APPENDIX B]

ELECTRONIC ORDER OF BATTLE (EOB) - The identification, location, and disposition of electronic systems of a military organization. [] NOTE: When the electronic systems of interest are limited to radar systems, the corresponding term is RADAR ORDER OF BATTLE.

ELECTRONIC POSTMARK (EPM) - A form of digital certification that appends to an e-mail message a date-time group that would be legally valid in a court. [] NOTE: E-mail messages which have electronic postmarks are accompanied by a special icon which, if clicked, will reveal the date-time group of the message.

ELECTRONIC PROTECTION (EP) - (1) That division of ELECTRONIC WARFARE involving actions taken to protect personnel, facilities, and equipment from any effects of friendly or enemy employment of electronic warfare that degrade, neutralize, or destroy friendly combat capability. [7:CJCS MOP 6, APPENDIX B] (2) That division of INFORMATION WARFARE (IW) involving measures used to defeat ELECTRONIC ATTACK (EA). [12] (3) The protection of forces against any friendly or enemy employment of Electronic Warfare that would degrade or deny friendly force combat capabilities. Electronic Protection addresses the EW problem of electronic interference and electronic fratricide. Formerly [10:2463], and synonymous [12] with ELECTRONIC COUNTER-COUNTERMEASURES.

ELECTRONIC RECONNAISSANCE - The detection, identification, evaluation, and location of foreign electromagnetic radiation emanating from other than nuclear detonations or radioactive sources. [1]

ELECTRONIC TAGGING - A system consisting of a light-weight wrist strap data tag, both waterproof and protected against electrostatic discharge, containing miniature non-volatile memory modules, which is secured on a person (say, a prisoner). Data describing the person is then loaded into the wrist-strap data tag where it remains until no longer needed (e.g., the prisoner's release). The other part of this system uses a PC-based handheld reader for reading and writing of the data tag. Data are then uploaded to a remote PC. The data tags can hold up to 100 times more data than the average bar code. Electronic tagging may also be used for hospital patients, inventory control, and security marking of property. [10:2527]

ELECTRONIC TIME STAMP - The marking of a digital document (data file, audio track, video track, photograph, etc.) with a digital time-of-receipt fingerprint unique to the document to subsequently establish chronology and prove authenticity. In order to prevent backward or forward dating by the time-stamping service, each digital signature is linked to the preceding time stamp. See also ELECTRONIC NOTARY. []

ELECTRONIC WARFARE (EW) - (1) Military action involving the use of electromagnetic energy to determine, exploit, reduce or prevent hostile use of the electromagnetic spectrum and action which retains friendly use of the electromagnetic spectrum. Also called EW. There are three divisions within electronic warfare: (a) ELECTRONIC COUNTERMEASURES, (b) ELECTRONIC COUNTER-COUNTERMEASURES, and (c) ELECTRONIC WARFARE SUPPORT MEASURES. [1] (2) Any military action involving the use of electromagnetic and directed energy to control the electromagnetic spectrum or to attack the enemy. The three major subdivisions within electronic warfare are electronic attack, electronic protection, and electronic warfare support: a. Electronic Attack (EA). That division of electronic warfare involving the use of electromagnetic or directed energy to attack personnel, facilities, or equipment with the intent of degrading, neutralizing, or destroying enemy combat capability. Electronic Attack includes: 1) Actions taken to prevent or reduce an enemy's effective use of the electromagnetic spectrum, such as jamming and electromagnetic deception; and 2) Employment of weapons that use either electromagnetic or directed energy as their primary destructive mechanism (laser, RF weapons, particle beams). b. Electronic Protection (EP). That division of electronic warfare involving actions taken to protect personnel, facilities, and equipment from any effects of friendly or enemy employment of electronic warfare that degrade, neutralize, or destroy friendly combat capability. c. Electronic Warfare Support (ES). That division of electronic warfare involving actions tasked by, or under direct control of, an operational commander to search for, intercept, identify, and locate sources of intentional and unintentional radiated electromagnetic energy for the purpose of immediate threat recognition. Thus, electronic warfare support provides information required for immediate decisions involving electronic warfare operations and other tactical actions such as threat avoidance, targeting, and homing. Electronic warfare support data can be used to produce signals intelligence (SIGINT), both COMMUNICATIONS INTELLIGENCE (COMINT) and ELECTRONICS INTELLIGENCE (ELINT). [7:CJCS MOP 6, APPENDIX B] See also NAVIGATION WARFARE (NAVWAR) NOTE: Electronic warfare is a part of offensive information operations.

ELECTRONIC WARFARE BATTLE TIMELINE - The sequence of events relating to a naval engagement are pre-timeline planning; surveillance / reconnaissance; acquisition; targeting; weapons direction and guidance; homing and fuzing; and post-timeline assessment. [10:43] NOTE: The sequence may cycle through the first two, three, or four events indefinitely in non-weapon exchange situations.

ELECTRONIC WARFARE COMMAND AND CONTROL (EWC2) - The exercise of authority and direction by a properly designated EW commander over assigned forces in the accomplishment of the EW mission. EW command and control functions are performed through an arrangement of personnel, equipment, communications, facilities, and procedures employed by a commander in planning, directing, coordinating, and controlling forces and operations in the accomplishment of the EW mission. [Adapted from the definition of Command and Control in reference 1]

ELECTRONIC WARFARE EFFECTIVENESS ASSESSMENT - The determination of the degree to which EW action achieved the desired result. See also BATTLE DAMAGE ASSESSMENT. [] NOTE: This measure may be estimated through analysis of data collected by both active and passive means - for example, by using radar or visual systems to detect changes in enemy weapons flight and trajectory profiles; or by using ESM to detect changes in the mode of radiated signals, communications volume, and other transmitted signal characteristics.

ELECTRONIC WARFARE MISSION - The task, together with the purpose, which clearly indicates the EW action to be taken, the spectral region to be covered, and the reason therefore. []

ELECTRONIC WARFARE REPROGRAMMABLE LIBRARY (EWRL) - A machine-retrievable EW database used by reprogrammable EW systems. [] NOTE: The mission of the U.S. Navy EWRL Support Program is "to produce, manage, and maintain tactical electronic warfare reprogrammable libraries for automated EW systems to ensure that operational forces can employ full capabilities of reprogrammable EW systems".

ELECTRONIC WARFARE REQUIRED OPERATIONAL CAPABILITY (EW ROC) - Qualitative and quantitative system performance parameters, proposed by the user, and approved by the DON, that are primary indicators of a system's capability to accomplish its mission (operational effectiveness) and to be supported (operational suitability). [10:SECNAVINST 5000.2]

ELECTRONIC WARFARE STRATEGY - The art and science of developing and using Electronic Warfare as necessary during peace and war, to afford the maximum support to policies, in order to enhance friendly usage of and impede the adversary's usage of the ELECTROMAGNETIC SPECTRUM. [Patterned after the definition of "Strategy" in reference 1]

ELECTRONIC WARFARE SUPPORT (ES or EWS) - (1) (ES) That division of electronic warfare involving actions tasked by, or under direct control of, an operational commander to search for, intercept, identify, and locate sources of intentional and unintentional radiated electromagnetic energy for the purpose of immediate threat recognition. Thus, electronic warfare support provides information required for immediate decisions involving electronic warfare operations and other tactical actions such as threat avoidance, targeting, and homing. Electronic warfare support data can be used to produce SIGNALS INTELLIGENCE (SIGINT), both COMMUNICATIONS INTELLIGENCE (COMINT) and ELECTRONICS INTELLIGENCE (ELINT). [7:CJCS MOP 6, APPENDIX B] (2) Those collection actions tasked by, and under the direct control of, an operational commander, primarily geared toward tactical support of the joint commander. Formerly ELECTRONIC SUPPORT MEASURES. [10:2463]

ELECTRONIC WARFARE SUPPORT MEASURES (ESM) - That division of electronic warfare involving actions taken under direct control of an operational commander to search for, intercept, identify, and locate sources of radiated electromagnetic energy for the purpose of immediate threat recognition. Thus, electronic warfare support measures (ESM) provide a source of information required for immediate decisions involving Electronic Countermeasures (ECM), Electronic Counter-Countermeasures (ECCM), avoidance, targeting, and other tactical employment of forces. Electronic warfare support measures data can be used to produce signals intelligence (SIGINT), both communications intelligence (COMINT) and electronics intelligence (ELINT). Also called ESM. Increasingly replaced by ELECTRONIC WARFARE SUPPORT, sometimes called ELECTRONIC SUPPORT MEASURES. [1] See also CRYPTOLOGIC ESM, FERRET RECEIVER. NOTE: In Frequency Hopping, the total available bandwidth is the spread bandwidth; however, the instantaneous bandwidth is less than the spread bandwidth. This technique is used in communications, radar, jamming, and other applications.

ELECTRONICS INTELLIGENCE (ELINT) - Technical and intelligence information derived from foreign non-communications electromagnetic radiation emanating from other than nuclear detonations or radioactive sources. [1]

ELECTRONICS SECURITY (ELSEC) - The protection resulting from all measures designed to deny unauthorized persons information of value that might be derived from their interception and study of non-communications electromagnetic radiation, e.g., radar. [1]

ELECTRO-OPTIC SPECTRUM
ULTRAVIOLET	0.01 - 0.4 microns
VISIBLE LIGHT	0.4 - 0.75 microns
NEAR INFRARED	0.75 - 3.00 microns
MID INFRARED	3.00 - 6.00 microns
FAR INFRARED	6.00 - 15.00 microns
EXTREME INFRARED	15.00 - 1,000.00 microns

ELECTRO-OPTICAL INTELLIGENCE (ELECTRO-OPTINT) - Intelligence information, other than signals intelligence, derived from the optical monitoring of the electromagnetic spectrum from ultraviolet (0.01 micrometers) through far infrared (1,000 micrometers). [1]

ELECTRO-OPTICS - The technology associated with those components, devices and systems which are designed to interact between the electromagnetic (optical) and the electric (electronic) state. Examples: Television; fiber optics. [1] See also KERR EFFECT. For additional discussion, click . [11.2]

ELECTROPHONIC EFFECT - A buzzing or clicking sound in the back of the head experienced by a person subjected to pulsed microwave radiation, such as from a SKULL TO VOICE (V2K) DEVICE. The absorbed energy produces a thermoelastic expansion of the brain tissue causing an acoustic pressure wave which is detected by the hair cells of the organ of Corti (a spiral structure within the cochlea containing hair cells that are stimulated by sound vibrations. The hair cells convert the vibrations into nerve impulses that are transmitted to the brain. ). [10:2797]

ELECTROTHERMAL GUN - A gun which uses electric energy and liquid propellant to achieve very high projectile velocities. [10:64]

EMBEDDED AVIONICS - Avionic sensors and processors, covering the electromagnetic spectrum, within the skin of an aircraft. Also known as SMART SKIN. [10:96]

EMERALD - Acronym for Event Monitoring Enabling Responses to Anomalous Live Disturbances. EMERALD is a cyberdefense tool designed to detect computer HACKERS and other intruders. Because it is "anomaly-based", EMERALD is able to detect novel attacks to which no computer system has ever been exposed before. [10:2842] NOTE: While EMERALD is able to detect attacks, it is not designed to respond to them.

EMERGENCY ROCKET COMMUNICATIONS SYSTEM (ERCS) - A 1960s-era system to provide emergency UHF communications by launching a rocket that would transmit pre-recorded force messages to all units within line of sight of the carrying rocket's apogee flight. [] NOTE: The ERCS was inactivated in the 1990s.

EMERGENCY WAR ORDER (EWO) - An order, issued by the President of the United States (POTUS), Secretary of Defense (SECDEF), or some other authorized command authority which initiates the employment of US nuclear weapon resources. []

EMISSION CONTROL (EMCON) - The selective and controlled use of electromagnetic, acoustic, or other emitters to optimize command and control capabilities while minimizing, for operations security (OPSEC), detection by enemy sensors; to minimize mutual interference among friendly systems; and/or to execute a military deception plan. See also RADAR SILENCE, RADIO SILENCE. [1]

EMISSION SECURITY (EMSEC) - Protection that results from all measures designed to deny unauthorized persons information of value that might be derived from intercept and analysis of compromising emanations. []

EMISSIVE CHAFF - CHAFF that also emits infrared (IR) radiation to deceive both RF and IR sensors on weapons. [8]

END GAME - The period of military engagement 3-5 seconds before missile impact. [10:2536] Also called ENDGAME.

ENERGETIC MATERIALS - A collective term for military high explosives, propellants and pyrotechnics that can sustain a steady state burning rate. [12] Synonymous with MILITARY EXPLOSIVES.

ENGINEER AND MINE WARFARE (EMW) - A military operations mission area consisting of five major battlefield functions: mobility, countermobility, survivability, sustainment engineering, and topographic engineering. [10:2734]

ENHANCED FIBER OPTIC GUIDED MISSILE (EFOG-M) - A multi-purpose precision kill weapon system. It enables a gunner in defilade to engage and defeat threat armored combat vehicles, other high value ground targets, and hovering or moving rotary wing aircraft that may be masked from line-of-sight direct fire weapon systems. [10:2744]

ENHANCED HYPERVELOCITY LAUNCHER (EHVL) - A 60-foot long multi-stage light gas gun that creates pressures of up to a million atmopheres. It has (reported in 1994) accelerated a 10 mm diameter titanium alloy flyer plate to 13.5 km/s (about 25 times the speed of a high-powered rifle bullet). []

ENGINE-DISABLING DEVICE - (1) A NONLETHAL WEAPON for disabling an engine such as that of a fleeing car by means of a high voltage discharge that perturbs or destroys the electrical circuits. (2) A NONLETHAL WEAPON consisting of airborne agents to choke engines or cause them to stall out. []

ENTANGLEMENTS - NONLETHAL WEAPON anti-personnel devices consisting of submunitions which release wire intended to entangle target individuals, or sticky nets intended to entangle fleeing individuals. []

ERIEYE - A Swedish-developed Airborne Early Warning & Control (AEW&C) Doppler-based radar capable of detecting fast-moving targets against surface backgrounds. It can track more than 200 tracks simultaneously, and can discriminate individual aircraft in a multiple-aircraft target track. [Ericsson Erieye announcement]

ERLANG - A unit of communications link traffic intensity equivalent to the fraction of time that the link is occupied. []

ERROR CORRECTING CODE (ECC) - A Code in which each data signal conforms to specific rules of construction so that departures from this construction in the received signals can be automatically detected, and permits automatic correction, at the received terminal, of some or all of the errors. [3]

ESCROWED ENCRYPTION - An encryption strategy wherein a third party is appointed by the state to keep a copy of the decryption keys, i.e., in escrow, for the state to use to decrypt any file sent to or by any user. [10:2815]

ESM INTERCEPT RANGE - A range roughly equal to one-and-a-half times the theoretical radar range. [] NOTE: This is a rule of thumb. Actual intercept range is affected by many factors, including propagation anomalies, transmission paths, background noise, etc.

ETHERNET - A passive baseband (digital transmission of data up to 10 million bits per second) local area network (LAN). [] NOTE: Ethernet conforms to IEEE 802.3 Standard for Carrier Sense Multiple Access with Collision Detect (CSMA/CD).

EVASIVE MANEUVERS BMD COUNTERMEASURES - A high-altitude countermeasure to make it difficult for the defender's missile to hit the part of the target that actually contains the warhead. A small rocket motor on the assembly containing the warhead starts the entire assembly tumbling. Another tactic is to deploy inflated balloons to make the entire tumbling assembly appear to be longer to the homing interceptor. Additional tethered balloons would present a complex target to the interceptor, making it impossible to determine the location of the warhead. [10:2609] See also FALSE-TARGET BMD COUNTERMEASURES, SHROUDING BMD COUNTERMEASURES, SUBMUNITION BMD COUNTERMEASURES, TRAJECTORY BMD COUNTERMEASURES.

EVOLUTIONARY COMPUTING (EC) - An approach to computing which is based on analogues of natural selection. EC may employ GENETIC ALGORITHMS, genetic programming, evolutionary strategies, and artificial life. [10:2783]

EXFILTRATION ROCKET (ER) - A system which quickly extracts special operations forces (SOF) teams from the mission area. [USAF 2025 study]

EXPANDED MEMORY - Additional RANDOM ACCESS MEMORY (RAM) which is swapped in and out of the 1Mb memory address of an 8088-class (i.e., original PC) computer through the use of special boards and software called expanded memory managers (EMM) which create the effect of having up to 32 Mb of memory. [] Compare with EXTENDED MEMORY.

EXPENDABLE ACOUSTIC REMOTE SENSOR (EARS) - A gun-emplaced passive acoustic sensor which autonomously detects and classifies vehicles by their acoustic signature and reports the results via telemetry. [10:2731]

EXPERT SYSTEM (ES) - (1) A computer program that embodies the expertise of one or more experts in some domain and applies this knowledge to make useful inferences for the user of the system. [10:10] (2) A program that solves problems competently at an expert level in a particular domain. The system uses a knowledge base, which is separate from the part of the program that does the inferencing using the knowledge base. An expert system is capable of dealing with incomplete knowledge and is able to explain its reasoning and conclusions. Synonymous with KNOWLEDGE-BASED SYSTEM. NOTE: One feature of expert systems that distinguishes them from conventional computer programs is that of the "explanation facility" which provides easy access by the user to the chain of reasoning that produced a given result (i.e., the user can ask "Why?" at any point).

EXPLOSIVE MAGNETIC FLUX COMPRESSOR - A device in which energy from a capacitor charges an inductor, which is then compressed rapidly by detonating an explosive. To conserve magnetic flux in the inductor, the inductor current increases as its area and inductance decreases. The result is a large pulse of current that can be employed in DIRECTED ENERGY WEAPONs. [10:16] Also called EXPLOSIVE FLUX COMPRESSION GENERATOR. NOTE: With delivered power levels of terawatts ot tens of terawatts, a large flux generator can produce electrical currents which are three orders of magnitude greater that those produced by a typical lightning stroke. [10:2824]

EXPLOSIVE SPLICING - A process of splicing wires by enclosing and metallurgically bonding the wires within copper sheets through use of explosive ribbons. [10:101] NOTE: This process is especially useful for joining small diameter conductor wires with results superior to solder joints. Explosively-spliced wires display stability at high temperature, and show no susceptibility to corrosion in contacts between dissimilar metals.

EXPLOSIVE STANDOFF MINE CLEARER (ESMC) - An explosive counter-mine system that creates a vehicle-wide lane by explosively neutralizing all surface and buried anti-tank (AT) mines from a position outside their lethal radii. The ESMC consists of a rocket-propelled explosive neutralization system (ENS) with shaped-charge munitions embedded in an oblong net. See also EXPLOSIVE STAND-0OFF MINEFIELD BREACHER. [] NOTE: The ESMC attacks the explosive components of the mines, not their firing mechanisms.

EXPLOSIVE STAND-OFF MINEFIELD BREACHER (ESMB) - An explosive system designed for in-stride clearing of mine fields in the path of an advancing tank force. The system consists of a mesh webbing, 5 meters wide and 145 meters long, containing more than 25,000 closely-spaced shaped explosive charges. The web is rocket-launched onto a suspected mine field ahead of an advancing tank column. Mines are destroyed by plasma jets produced by the detonation of the shaped charges. [10:2702]

EXTREMELY LOW FREQUENCY (ELF) - A communications system for transmitting short messages from operating authorities in the Continental United States (CONUS) at extremely low frequencies to submerged submarines which are at operating depths and speeds. [SPAWAR] See also FIXED VERY LOW FREQUENCY (FVLF) NOTE: ELF operates in the 40 - 80 Hz region using antennas between 45 and more than 200 km in length. It employs the phenomenon of ionospheric refraction.

EYE-SAFE - Pertains to laser devices such as laser rangefinders. If human eyes are inadvertently lased by the device, there is no risk of retinal damage. See also LOW ENERGY LASER WEAPON. []