A
directed-energy weapon (
DEW) emits
energyIn physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
in an aimed direction without the means of a
projectileA projectile is any object projected into space by the exertion of a force. Although a thrown baseball is technically a projectile too, the term more commonly refers to a weapon....
. It transfers energy to a target for a desired effect. Intended effects may be non-lethal or lethal. Some such weapons are real, or are under active
research and developmentThe phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...
.
The energy can come in various forms:
- Electromagnetic radiation
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object....
, in laserA laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
s or maserA maser is a device that produces coherent electromagnetic waves through amplification by stimulated emission. Historically, “maser” derives from the original, upper-case acronym MASER, which stands for "Microwave Amplification by Stimulated Emission of Radiation"...
s
- Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
- Particles with mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
, in particle beam weaponA particle beam weapon uses an ultra-high-energy beam of atoms or electrons to damage a material target by hitting it, and thus disrupting its atomic and molecular structure. A particle beam weapon is a type of directed-energy weapon, which directs energy in a particular direction by a means of...
s
- Flamethrowers
- Sound
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...
, in sonic weapons
Some such weapons, perhaps most, at present only appear in
science fictionScience fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...
, non-functional
toyA toy is any object that can be used for play. Toys are associated commonly with children and pets. Playing with toys is often thought to be an enjoyable means of training the young for life in human society. Different materials are used to make toys enjoyable and cuddly to both young and old...
s,
film propsA theatrical property, commonly referred to as a prop, is an object used on stage by actors to further the plot or story line of a theatrical production. Smaller props are referred to as "hand props". Larger props may also be set decoration, such as a chair or table. The difference between a set...
or
animationAnimation is the rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of movement. The effect is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in several ways...
.
In science fiction, these weapons are sometimes known as death rays or
raygunRayguns are a type of fictional directed-energy weapon. They have various alternate names: ray gun, death ray, beam gun, blaster, laser gun, phaser, etc. They are a well-known feature of science fiction; for such stories they typically have the general function of guns...
s and are usually portrayed as projecting energy at a person or object to kill or destroy. Many modern examples of science fiction have more specific names for directed energy weapons, due to research advances.
Operational advantages
Laser weapons could have several main advantages over conventional weaponry:
- Laser beams travel at the speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
, so there is no need (except over very long distances) for users to compensate for target movement when firing over long distances. Consequently, evading a laser after it has been fired is impossible.
- Light does not have mass, so is little influenced by gravity, so that long range projection requires little compensation. Other aspects such as wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
speed can be neglected at most times, unless shooting through clouds.
- Lasers can change focusing configuration to provide an active area that can be much smaller or larger than projectile weaponry.
- Given a sufficient power source, laser weapons could essentially have limitless ammunition.
- Because light has a practically nil ratio (exactly
) of momentumIn classical mechanics, linear momentum or translational momentum is the product of the mass and velocity of an object...
to energyIn physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
, lasers produce negligible recoilRecoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...
.
- The operational range of a laser weapon can be much larger than that of a ballistic weapon, depending on atmospheric conditions and power level.
Modern ballistic weapons commonly feature systems to counter many undesirable side-effects mentioned for them in the above comparison. As such it follows that laser weapons' advantage over ballistics could end up more about elegance and cost.
Blooming
Laser beams begin to cause
plasmaIn physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
breakdown in the air at energy densities of around a
megajouleThe joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...
per cubic centimeter. This effect, called "blooming," causes the laser to defocus and disperse energy into the atmosphere. Blooming can be more severe if there is
fogFog is a collection of water droplets or ice crystals suspended in the air at or near the Earth's surface. While fog is a type of stratus cloud, the term "fog" is typically distinguished from the more generic term "cloud" in that fog is low-lying, and the moisture in the fog is often generated...
,
smokeSmoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires , but may also be used for pest...
, or
dustDust consists of particles in the atmosphere that arise from various sources such as soil dust lifted up by wind , volcanic eruptions, and pollution...
in the air.
Reducing blooming:
- Spread the beam across a large, curved mirror that focuses the power on the target, to keep energy density en route too low for blooming to happen. This requires a large, very precise, fragile mirror, mounted somewhat like a searchlight, requiring bulky machinery to slew the mirror to aim the laser.
- Use a phased array
In wave theory, a phased array is an array of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions.An antenna array...
. For typical laser wavelengthIn physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s this method requires billions of micrometreA micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
-size antennaeAn antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
. No way to make these is known. However, carbon nanotubeCarbon nanotubes are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1, significantly larger than for any other material...
s have been proposed. Phased arrays could theoretically also perform phase-conjugate amplificationNonlinear optics is the branch of optics that describes the behavior of light in nonlinear media, that is, media in which the dielectric polarization P responds nonlinearly to the electric field E of the light...
(see below). Phased arrays do not require mirrors or lenses, can be made flat and thus do not require a turret-like system (as in "spread beam") to be aimed, though range will suffer at extreme angles (that is, the angle the beam forms to the surface of the phased array).
- Use a phase-conjugate laser system. Here, a "finder" or "guide" laser illuminates the target. Any mirror-like ("specular") points on the target reflect light that is sensed by the weapon's primary amplifier. The weapon then amplifies inverted waves in a positive feedback loop, destroying the target with shockwaves
A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...
as the specular regions evaporate. This avoids blooming because the waves from the target passed through the blooming, and therefore show the most conductive optical path; this automatically corrects for the distortions caused by blooming. Experimental systems using this method usually use special chemicals to form a "phase-conjugate mirror". In most systems, the mirror overheats dramatically at weapon-useful power levels.
- Use a very short pulse that finishes before blooming interferes.
- Focus multiple lasers of relatively low power on a single target.
Evaporated target material
Another problem with weaponized lasers is that the evaporated material from the target's surface begins to shade. There are several approaches to this problem:
- Induce a standing shockwave in the ablation
Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. This occurs in spaceflight during ascent and atmospheric reentry, glaciology, medicine, and passive fire protection.-Spaceflight:...
cloud. The shockwaveA shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...
then continues to perform damage.
- Scan the target faster than the shockwave propagates
- Induce plasmic optical mixing at the target. Modulate the transparency of the target's ablation cloud to one laser by another laser, perhaps by tuning the laser to the absorption spectra of the ablation cloud, and inducing population inversion
In physics, specifically statistical mechanics, a population inversion occurs when a system exists in state with more members in an excited state than in lower energy states...
in the cloud. The other laser then induces local lasing in the ablation cloud. The beat frequency that results can induce frequencies that penetrate the ablation cloud.
High power consumption
One major problem with laser weapons (and directed-energy weapons in general) is their high electric energy requirements. Existing methods of storing, conducting, transforming, and directing energy are inadequate to produce a convenient hand-held weapon. Existing lasers waste much energy as heat, requiring still-bulky cooling equipment to avoid overheating damage. Air cooling could yield an unacceptable delay between shots. These problems, which severely limit laser weapon practicality at present, might be offset by:
- Cheap high-temperature superconductors
Superconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum...
to make the weapon more efficient.
- More convenient high volume electricity storage/generation. Part of the energy could be used to cool the device.
Chemical laserA chemical laser is a laser that obtains its energy from a chemical reaction. Chemical lasers can achieve continuous wave output with power reaching to megawatt levels...
s use energy from a suitable
chemical reactionA chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
instead.
Chemical oxygen iodine laserChemical oxygen iodine laser, or COIL, is an infrared chemical laser. As the beam is infrared, it cannot be seen with the naked eye. It is capable of output power scaling up to megawatts in continuous mode...
(
hydrogen peroxideHydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
with
iodineIodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
) and
deuterium fluoride laserThe hydrogen fluoride laser is an infrared chemical laser. It is capable of delivering continuous output power in the megawatt range.Hydrogen fluoride lasers operate at the wavelength of 2.7-2.9 µm. This wavelength is absorbed by the atmosphere, effectively attenuating the beam and reducing its...
(atomic
fluorineFluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...
reacting with
deuteriumDeuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...
) are two laser types capable of megawatt-range continuous beam output. Managing chemical fuel presents other problems, so the problems of cooling and overall inefficiency remain.
This problem could also be lessened if the weapon were mounted either at a defensive position near a power plant, or on board a large, possibly
nuclear poweredNuclear propulsion includes a wide variety of propulsion methods that fulfil the promise of the Atomic Age by using some form of nuclear reaction as their primary power source.- Surface ships and submarines :...
, water-going ship. A ship would have the advantage of water for cooling.
Beam absorption
A laser beam or particle beam passing through air can be absorbed or scattered by rain, snow, dust, fog, smoke, or similar visual obstructions that a bullet would easily penetrate. This effect adds to blooming problems and makes the dissipation of energy into the atmosphere worse.
The wasted energy can disrupt cloud development since the impact wave creates a "tunneling effect". Engineers from
MITThe Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
and the
U.S. ArmyThe United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
are looking into using this effect for
precipitationIn meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
management.
Lack of indirect fire capabilities
Indirect fireIndirect fire means aiming and firing a projectile in a high trajectory without relying on a direct line of sight between the gun and its target, as in the case of direct fire...
, as used in artillery warfare, can reach a target behind a hill, but is not feasible with line-of-sight DEWs. Possible alternatives are to mount the lasers (or perhaps just reflectors) on airborne or space-based platforms.
Lasers
Lasers are often used for sighting, ranging and targeting for guns; but the laser beam is not the source of the weapon's firepower.
Laser weapons usually generate brief high-energy pulses. A one megajoule laser pulse delivers roughly the same energy as 200 grams of high explosive, and has the same basic effect on a target. The primary damage mechanism is mechanical shear, caused by reaction when the surface of the target is explosively evaporated.
Most existing weaponized lasers are
gas dynamic laserGas Dynamic Laser is laser based on differences in relaxation velocities of molecular vibrational states.The laser medium gas has such properties that an energetically lower vibrational state relaxes faster than a higher vibrational state,...
s. Fuel, or a powerful
turbineA turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
, pushes the lasing media through a circuit or series of orifices. The high-pressures and heating cause the medium to form a plasma and lase. A major difficulty with these systems is preserving the high-precision mirrors and windows of the laser resonating cavity. Most systems use a low-powered "oscillator" laser to generate a coherent wave, and then amplify it. Some experimental laser amplifiers do not use windows or mirrors, but have open orifices, which cannot be destroyed by high energies.
Some lasers are used as non-lethal weapons, such as
dazzlerA dazzler is a directed-energy weapon intended to temporarily blind or disorient its target with intense directed radiation. Targets can include sensors or human vision. Dazzlers emit infrared or visible light against various electronic sensors, and visible light against humans, when they are...
s which are designed to temporarily blind or distract.
- Examples are listed at List of applications for lasers#Directly as an energy weapon.
Electrolaser
An electrolaser lets blooming occur, and then sends a powerful electric current down the conducting
ionizedIonization is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions. This is often confused with dissociation. A substance may dissociate without necessarily producing ions. As an example, the molecules of table sugar...
track of plasma so formed, somewhat like
lightningLightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
. It functions as a giant high energy long-distance version of the
TaserA Taser is an electroshock weapon that uses electrical current to disrupt voluntary control of muscles. Its manufacturer, Taser International, calls the effects "neuromuscular incapacitation" and the devices' mechanism "Electro-Muscular Disruption technology"...
or stun gun.
Radio frequency
High-energy radio-frequency weapons (HERF) work on the same principles as
microwaveMicrowaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
ovens, have also shown potential.
On January 25, 2007 the US Army unveiled a device mountable on a small armored vehicle (Humvee). It resembles a planar array. It can make people feel as if the skin temperature is around 130 °F (54.4 °C) from around 500 yards (457.2 m) away. Full scale production of such a weapon was not expected until at least 2010. It is probably most usefully deployed as an
Active Denial SystemThe Active Denial System is a non-lethal, directed-energy weapon developed by the U.S. military. It is a strong millimeter-wave transmitter primarily used for crowd control . Some ADS such as HPEM ADS are also used to disable vehicles. Informally, the weapon is also called the heat ray...
.
Microwaves
MicrowaveMicrowaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
guns powerful enough to injure humans are possible:
- Active Denial System
The Active Denial System is a non-lethal, directed-energy weapon developed by the U.S. military. It is a strong millimeter-wave transmitter primarily used for crowd control . Some ADS such as HPEM ADS are also used to disable vehicles. Informally, the weapon is also called the heat ray...
is a millimeter wave source that heats the water in the target's skin and thus causes incapacitating pain. It is being used by the U.S. Air Force Research LaboratoryThe Air Force Research Laboratory is a scientific research organization operated by the United States Air Force Materiel Command dedicated to leading the discovery, development, and integration of affordable aerospace warfighting technologies; planning and executing the Air Force science and...
and RaytheonRaytheon Company is a major American defense contractor and industrial corporation with core manufacturing concentrations in weapons and military and commercial electronics. It was previously involved in corporate and special-mission aircraft until early 2007...
for riot-control duty. Though intended to cause severe pain while leaving no lasting damage, some concern has been voiced as to whether the system could cause irreversible damage to the eyes. There has yet to be testing for long-term side effects of exposure to the microwave beam. It can also destroy unshieldedTEMPEST is a codename referring to investigations and studies of compromising emission . Compromising emanations are defined as unintentional intelligence-bearing signals which, if intercepted and analyzed, may disclose the information transmitted, received, handled, or otherwise processed by any...
electronicsElectronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
. The device comes in various sizes including attached to a humvee.
- Vigilant Eagle
The Vigilant Eagle Airport Protection System is a proposed directed-energy weapon under development by the U.S. military under a Defense Department contract with Raytheon...
is an airport defense system that directs high-frequency microwaves towards any projectile that is fired at an aircraft. The system consists of a missile–detecting and tracking subsystem (MDT), a command and control system, and a scanning array. The MDT is a fixed grid of passive infrared (IR) cameras. The command and control system determines the missile launch point. The scanning array projects microwaves that disrupt the surface-to-air missile's guidance system, deflecting it from the aircraft.
- Bofors HPM Blackout is a versatile and compact stand alone High Power Microwave system suitable for evaluation, research and as a decision tool for microwave effects and/or protection. With this system a realistic perspective is possible with regard to tactical adaptation and the generated level of microwave radiation. Bofors HPM Blackout has proven destructive effects at considerable distance against a broad field of COTS equipment.
Pulsed Energy Projectile
Pulsed Energy Projectile or PEP systems emit an infrared laser pulse which creates rapidly expanding
plasmaIn physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
at the target. The resulting sound, shock and electromagnetic waves stun the target and cause pain and temporary paralysis. The weapon is under development and is intended as a non-lethal weapon in crowd control.
Particle beam weapons
Particle beam weapons can use charged or neutral particles, and can be either endoatmospheric or exoatmospheric.
Particle beamA particle beam is a stream of charged or neutral particles which may be directed by magnets and focused by electrostatic lenses, although they may also be self-focusing ....
s as beam weapons are theoretically possible, but practical weapons have not been demonstrated. Certain types of particle beams have the advantage of being self-focusing in the atmosphere.
Blooming is also a problem in particle beam weapons. Energy that would otherwise be focused on the target spreads out; the beam becomes less effective:
- Thermal blooming occurs in both charged and neutral particle beams, and occurs when particles bump into one another under the effects of thermal vibration, or bump into air molecules.
- Electrical blooming occurs only in charged particle beams, as ions of like charge repel one another.
Plasma weapons
Plasma weapons fire a beam, bolt, or
streamA particle beam is a stream of charged or neutral particles which may be directed by magnets and focused by electrostatic lenses, although they may also be self-focusing ....
of
plasmaIn physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
, which is an excited
state of matterStates of matter are the distinct forms that different phases of matter take on. Solid, liquid and gas are the most common states of matter on Earth. However, much of the baryonic matter of the universe is in the form of hot plasma, both as rarefied interstellar medium and as dense...
consisting of atomic electrons & nuclei and free electrons if
ionizedIonization is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions. This is often confused with dissociation. A substance may dissociate without necessarily producing ions. As an example, the molecules of table sugar...
, or other particles if
pinchedA pinch is the compression of an electrically conducting filament by magnetic forces. The conductor is usually a plasma, but could also be a solid or liquid metal...
.
The
MARAUDERMARAUDER is, or was, a United States Government research project. It is an acronym of Magnetically Accelerated Ring to Achieve Ultra-high Directed Energy and Radiation. It was first reported on August 1, 1993....
(
Magnetically Accelerated Ring to Achieve Ultra-high Directed Energy and Radiation) used the
Shiva StarShiva Star, originally just SHIVA, is a high-powered pulsed-power research device located at the Air Force Research Laboratory on the Kirtland Air Force Base in Albuquerque, New Mexico...
project (a high energy capacitor bank which provided the means to test weapons and other devices requiring brief and extremely large amounts of energy) to accelerate a toroid of plasma at a significant percentage of the speed of light.
Electric beam in a vacuum
In a
vacuumIn everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
(e.g. in
spaceSpace is the boundless, three-dimensional extent in which objects and events occur and have relative position and direction. Physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum...
), an electric discharge can travel a potentially unlimited distance at a velocity slightly slower than the speed of light. This is because there is no significant electric resistance to the flow of electric current in a vacuum. This would make such devices useful to destroy the
electricalElectricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
and
electronicElectronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
parts of
satelliteIn the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s and
spacecraftA spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
. However, in a vacuum the electric current cannot ride a laser beam, and some other means must be used to keep the electron beam on track and to prevent it from dispersing: see
particle beamA particle beam is a stream of charged or neutral particles which may be directed by magnets and focused by electrostatic lenses, although they may also be self-focusing ....
.
Speed of the weapon
The speed of the energy weapon is determined by the density of the beam. If it is very dense then it is very powerful, but a particle beam moves much slower than the
speed of lightThe speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
. Its speed is determined by mass, power, density, or particle/energy density.
Sonic weapons
Cavitation, which affects gas nuclei in human tissue, and heating can result from exposure to ultrasound and can damage tissue and organs. Studies have found that exposure to high intensity ultrasound at frequencies from 700 kHz to 3.6 MHz can cause lung and intestinal damage in mice. Heart rate patterns following vibroacoustic stimulation have resulted in serious arterial flutter and
bradycardiaBradycardia , in the context of adult medicine, is the resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min. It may cause cardiac arrest in some patients, because those with bradycardia may not be pumping enough oxygen to their heart...
. Researchers have concluded that generating pain through the auditory system using high intensity sound risked permanent hearing damage.
A multi-organization research program involved high intensity audible sound experiments on human subjects. Extra-aural (unrelated to hearing) bioeffects on various internal organs and the central nervous system included auditory shifts, vibrotactile sensitivity change, muscle contraction, cardiovascular function change,
central nervous systemThe central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
effects,
vestibularThe Vestibular is a competitive examination and is the primary and widespread system used by Brazilian universities to select their students. The Vestibular usually takes place from November to January, right before the start of school year in February or March, although certain universities hold...
(
inner earThe inner ear is the innermost part of the vertebrate ear. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:...
) effects, and chest wall/lung tissue effects. Researchers found that low frequency sonar exposure could result in significant
cavitationCavitation is the formation and then immediate implosion of cavities in a liquidi.e. small liquid-free zones that are the consequence of forces acting upon the liquid...
s,
hypothermiaHypothermia is a condition in which core temperature drops below the required temperature for normal metabolism and body functions which is defined as . Body temperature is usually maintained near a constant level of through biologic homeostasis or thermoregulation...
, and tissue shearing. Follow-on experiments were not recommended.
Tests performed on mice show the threshold for both lung and liver damage occurs at about 184
dBThe decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...
. Damage increases rapidly as intensity is increased. Noise-induced neurological disturbances in humans exposed to continuous low frequency tones for durations longer than 15 minutes involved development of immediate and long term problems affecting brain tissue. The symptoms resembled those of individuals who had suffered minor head injuries. One theory for a causal mechanism is that the prolonged sound exposure resulted in enough mechanical strain to brain tissue to induce an
encephalopathyEncephalopathy means disorder or disease of the brain. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of global brain dysfunction; this syndrome can be caused by many different illnesses.-Terminology:...
.
Ancient inventors
According to
legendA legend is a narrative of human actions that are perceived both by teller and listeners to take place within human history and to possess certain qualities that give the tale verisimilitude...
, the concept of the "burning mirror" or
death ray began with
ArchimedesArchimedes of Syracuse was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an...
who created a mirror with an adjustable focal length (or more likely, a series of mirrors focused on a common point) to focus sunlight on ships of the
RomanAncient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
fleet as they invaded Syracuse, setting them on fire. Historians point out that the earliest accounts of the battle did not mention a "burning mirror", but merely stated that Archimedes's ingenuity combined with a way to hurl fire were relevant to the victory. Some attempts to replicate this feat have had some success (though not on any of three attempts by the
MythBustersMythBusters is a science entertainment TV program created and produced by Beyond Television Productions for the Discovery Channel. The series is screened by numerous international broadcasters, including Discovery Channel Australia, Discovery Channel Latin America, Discovery Channel Canada, Quest...
television program). In particular, an experiment by students at
MITThe Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
showed that a mirror-based weapon was at least possible, if not necessarily practical.
Robert Watson-Watt
In 1935 the British
Air MinistryThe Air Ministry was a department of the British Government with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964...
asked
Robert Watson-WattSir Robert Alexander Watson-Watt, KCB, FRS, FRAeS is considered by many to be the "inventor of radar". Development of radar, initially nameless, was first started elsewhere but greatly expanded on 1 September 1936 when Watson-Watt became...
of the
Radio Research StationThe Radio Research Station 1924 - August 31, 1979 at Ditton Park, Buckinghamshire, England was the UK government research laboratory which pioneered the regular observation of the ionosphere by ionosondes in continuous operation since September 20, 1932, and applied the ionosonde technology for the...
whether a "
death rayRayguns are a type of fictional directed-energy weapon. They have various alternate names: ray gun, death ray, beam gun, blaster, laser gun, phaser, etc. They are a well-known feature of science fiction; for such stories they typically have the general function of guns...
" was possible. He and colleague Arnold Wilkins quickly concluded that it was not feasible, but as a consequence suggested using radio for the detection of aircraft and this started the development of
radarRadar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
in Britain. See: History of radar#Robert Watson-Watt.
Engine-stopping rays, urban legend made real
Engine-stopping rays are a variant that occurs in fiction and myth. Such stories were circulating in Britain around 1938. The tales varied but in general terms told of tourists whose car engine suddenly died and were then approached by a German soldier who told them that they had to wait. The soldier returned a short time later to say that the engine would now work and the tourists drove off. A possible origin of some of these stories arises from the testing of the television transmitter in
FeldbergFeldberg is a municipality in the district of Breisgau-Hochschwarzwald in Baden-Württemberg in southern Germany. It is located near the Feldberg. At an elevation of 1277m, it is considered the highest village in Germany.-External links:*...
, Germany. Because electrical noise from car engines would interfere with field strength measurements, sentries would stop all traffic in the vicinity for the twenty minutes or so needed for a test. A distorted retelling of the events might give rise to the idea that a transmission killed the engine.
A shoulder-mounted engine-stopping weapon was a central plot element in episode 303 of BBC espionage drama serial
SpooksSpooks is a British television drama series that originally aired on BBC One from 13 May 2002 – 23 October 2011, consisting of 10 series. The title is a popular colloquialism for spies, as the series follows the work of a group of MI5 officers based at the service's Thames House headquarters, in a...
, in which it was referred to as an "engine killer".
Modern car engines are not mechanically, but electronically controlled. Disabling the electronics can indeed stop the engine. This has been implemented in
OnStarOnStar Corporation is a subsidiary of General Motors that provides subscription-based communications, in-vehicle security, hands free calling, turn-by-turn navigation, and remote diagnostics systems throughout the United States, Canada and China. A similar service is known as ChevyStar in Latin...
, which has a remote control feature, but this is not a weapon. See also
electromagnetic pulseAn electromagnetic pulse is a burst of electromagnetic radiation. The abrupt pulse of electromagnetic radiation usually results from certain types of high energy explosions, especially a nuclear explosion, or from a suddenly fluctuating magnetic field...
(EMP), which is known for its engine-stopping effect, but is an undirected energy weapon.
Tesla
Nikola TeslaNikola Tesla was a Serbian-American inventor, mechanical engineer, and electrical engineer...
(1856–1943) was a noted inventor, scientist and electrical engineer. He invented
Tesla coilA Tesla coil is a type of resonant transformer circuit invented by Nikola Tesla around 1891. It is used to produce high voltage, low current, high frequency alternating current electricity. Tesla coils produce higher current than the other source of high voltage discharges, electrostatic machines...
s,
transformerA transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
s,
alternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
electrical generatorIn electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...
s and was the first early pioneer of
radioRadio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
technology. Tesla worked on plans for a directed-energy weapon from the early 1900s until his death. In 1937, Tesla composed a treatise entitled
The Art of Projecting Concentrated Non-dispersive Energy through the Natural Media concerning charged particle beams.
German World War II experimental weapons
In the later phases of
World War IIWorld War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
,
Nazi GermanyNazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
increasingly put its hopes on research into technologically revolutionary
secret weaponA secret weapon is either a concealed weapon, or a weapon that is not officially confirmed by the owner.In terms of large-scale weapons, a secret weapon may refer to a newly-designed or invented weapon that the government denies the existence of...
s, the
WunderwaffeWunderwaffe is German for "wonder-weapon" and was a term assigned during World War II by the German propaganda ministry to a few revolutionary "superweapons". Most of these weapons however remained more or less feasible prototypes, or reached the combat theatre too late, and in too insignificant...
n.
Among the directed-energy weapons the Nazis investigated were
X-RayX-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
Beam Weapons developed under Heinz Schmellenmeier, Richard Gans and Fritz Houtermans. They built an electron accelerator called Rheotron (invented by Max Steenbeck at
Siemens-SchuckertSiemens-Schuckert was a German electrical engineering company headquartered in Berlin, Erlangen and Nuremberg that was incorporated into the Siemens AG in 1966....
in the 1930s, these were later called
BetatronA betatron is a cyclotron developed by Donald Kerst at the University of Illinois in 1940 to accelerate electrons, but the concepts ultimately originate from Rolf Widerøe and previous development occurred in Germany through Max Steenbeck in the 1930s. The betatron is essentially a transformer with...
s by the Americans) to generate hard X ray synchrotron beams for the Reichsluftfahrtministerium (RLM). The intent was to pre-ionize ignition in Aircraft engines and hence serve as anti-aircraft DEW and bring planes down into the reach of the FLAK. The Rheotron was captured by the Americans in Burggrub on April 14, 1945.
Another approach was Ernst Schiebolds 'Röntgenkanone' developed from 1943 in Großostheim near
AschaffenburgAschaffenburg is a city in northwest Bavaria, Germany. The town of Aschaffenburg is not considered part of the district of Aschaffenburg, but is the administrative seat.Aschaffenburg is known as the Tor zum Spessart or "gate to the Spessart"...
. The Company Richert Seifert & Co from Hamburg delivered parts.
The Third Reich further developed
sonic weaponrySonic and ultrasonic weapons are weapons of various types that use sound to injure, incapacitate, or kill an opponent. Some sonic weapons are currently in limited use or in research and development by military and police forces. Others exist only in the realm of science fiction...
, using parabolic reflectors to project sound waves of destructive force. Microwave Weapons were investigated together with the Japanese.
Strategic Defense Initiative
In the 1980s,
U.S. PresidentThe President of the United States of America is the head of state and head of government of the United States. The president leads the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces....
Ronald ReaganRonald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....
proposed the
Strategic Defense InitiativeThe Strategic Defense Initiative was proposed by U.S. President Ronald Reagan on March 23, 1983 to use ground and space-based systems to protect the United States from attack by strategic nuclear ballistic missiles. The initiative focused on strategic defense rather than the prior strategic...
(SDI) program, which was nicknamed
Star WarsStar Wars is an American epic space opera film series created by George Lucas. The first film in the series was originally released on May 25, 1977, under the title Star Wars, by 20th Century Fox, and became a worldwide pop culture phenomenon, followed by two sequels, released at three-year...
. It suggested that lasers, perhaps space-based
X-ray laserAn X-ray laser is a device that uses stimulated emission to generate or amplify electromagnetic radiation in the near X-ray or extreme ultraviolet region of the spectrum, that is, usually on the order of several of tens of nanometers wavelength.Because of high gain in the lasing medium, short...
s, could destroy
ICBMsAn intercontinental ballistic missile is a ballistic missile with a long range typically designed for nuclear weapons delivery...
in flight. Though the strategic missile defense concept has continued to the present under the
Missile Defense AgencyThe Missile Defense Agency is the section of the United States government's Department of Defense responsible for developing a layered defense against ballistic missiles. The agency has its origins in the Strategic Defense Initiative, which was established in 1983 and was headed by Lt...
, most of the directed-energy weapon concepts were shelved.
Iraq War
During the
Iraq War, electromagnetic weapons, including high power microwaves were used by the U.S. military to disrupt and destroy the Iraqi electronic systems and may have been used for other purposes. Types and magnitudes of exposure to electromagnetic fields are unknown.
Non-lethal weapons
The TECOM Technology Symposium in 1997 concluded on non-lethal weapons, “Determining the target effects on personnel is the greatest challenge to the testing community,” primarily because "the potential of injury and death severely limits human tests."
Also, "directed energy weapons that target the central nervous system and cause neurophysiological disorders may violate the Certain Conventional Weapons Convention of 1980. Weapons that go beyond non-lethal intentions and cause “superfluous injury or unnecessary suffering” may also violate the Protocol I to the Geneva Conventions of 1977."
Some common bio-effects of non-lethal electromagnetic weapons include:
- Difficulty breathing
- Disorientation
Orientation is a function of the mind involving awareness of three dimensions: time, place and person. Problems with orientation lead to disorientation, and can be due to various conditions, from delirium to intoxication...
- Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
- Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
- Vertigo
Vertigo is a type of dizziness, where there is a feeling of motion when one is stationary. The symptoms are due to a dysfunction of the vestibular system in the inner ear...
- Other systemic discomfort.
Interference with breathing poses the most significant, potentially lethal results.
Light and repetitive visual signals can induce
epilepticEpilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
seizures.
VectionBecause human senses are adapted for use on the ground, navigating by sensory input alone during flight can be dangerous: sensory input does not always accurately reflect the movement of the aircraft, causing sensory illusions. These illusions can be extremely dangerous for pilots.-Vestibular...
and
motion sicknessMotion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement...
can also occur.
Cruise shipA cruise ship or cruise liner is a passenger ship used for pleasure voyages, where the voyage itself and the ship's amenities are part of the experience, as well as the different destinations along the way...
s are known to use sonic weapons to drive off pirates.
See also
- Electronic warfare
Electronic warfare refers to any action involving the use of the electromagnetic spectrum or directed energy to control the spectrum, attack an enemy, or impede enemy assaults via the spectrum. The purpose of electronic warfare is to deny the opponent the advantage of, and ensure friendly...
- Electromagnetic weapon
Electromagnetic weapons are a type of directed energy weapons which use electromagnetic radiation to deliver heat, mechanical, or electrical energy to a target to cause various, sometimes very subtle, effects. They can be used against humans, electronic equipment, and military targets generally,...
- German WW 2 Sonic Cannon
During the early 1940s Axis engineers developed a sonic cannon that could literally shake a person apart from the inside. A methane gas combustion chamber leading to two parabolic dishes pulse-detonated at roughly 44hz.- Health effects :...
- Laser applications
Many scientific, military, medical and commercial laser applications have been developed since the invention of the laser in the 1958. The coherency, high monochromaticity, and ability to reach extremely high powers are all properties which allow for these specialized applications.-Scientific:In...
- List of plasma (physics) applications articles
External links