Directed-energy weapon

A directed-energy weapon (DEW) emits energy in an aimed direction without the means of a projectile. 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 development.

The energy can come in various forms:

Some such weapons, perhaps most, at present only appear in science fiction, non-functional toys, film props or animation.

In science fiction, these weapons are sometimes known as death rays or rayguns 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.

Contents

Operational advantages

Laser weapons could have several main advantages over conventional weaponry:

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.

Problems and considerations

Blooming

Laser beams begin to cause plasma breakdown in the air at energy densities of around a megajoule 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 fog, smoke, or dust in the air.

Reducing blooming:

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:

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:

  1. Cheap high-temperature superconductors to make the weapon more efficient.
  2. More convenient high volume electricity storage/generation. Part of the energy could be used to cool the device.

Chemical lasers use energy from a suitable chemical reaction instead. Chemical oxygen iodine laser (hydrogen peroxide with iodine) and deuterium fluoride laser (atomic fluorine reacting with deuterium) 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 powered, 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 MIT and the U.S. Army are looking into using this effect for precipitation management.

Lack of indirect fire capabilities

Indirect 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

See also: Electromagnetic weapon

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 lasers. Fuel, or a powerful turbine, 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 dazzlers which are designed to temporarily blind or distract.

Examples are listed at List of applications for lasers#Directly as an energy weapon.

Electrolaser

Main article: Electrolaser

An electrolaser lets blooming occur, and then sends a powerful electric current down the conducting ionized track of plasma so formed, somewhat like lightning. It functions as a giant high energy long-distance version of the Taser or stun gun.

Radio frequency

High-energy radio-frequency weapons (HERF) work on the same principles as microwave 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 °C) from around 500 yards (460 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 System.

Microwaves

Microwave guns powerful enough to injure humans are possible:

Pulsed Energy Projectile

Main article: Pulsed Energy Projectile

Pulsed Energy Projectile or PEP systems emit an infrared laser pulse which creates rapidly expanding plasma 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

Main article: Particle beam weapon

Particle beam weapons can use charged or neutral particles, and can be either endoatmospheric or exoatmospheric. Particle beams 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:

Plasma weapons

Main article: Plasma weapon

Plasma weapons fire a beam, bolt, or stream of plasma, which is an excited state of matter consisting of atomic electrons & nuclei and free electrons if ionized, or other particles if pinched.

The MARAUDER (Magnetically Accelerated Ring to Achieve Ultra-high Directed Energy and Radiation) used the Shiva Star 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.[8]

Electric beam in a vacuum

In a vacuum (e.g. in space), 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 electrical and electronic parts of satellites and spacecraft. 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 beam.

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 light. Its speed is determined by mass, power, density, or particle/energy density.

Sonic weapons

Main article: Sonic weaponry

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 bradycardia. Researchers have concluded that generating pain through the auditory system using high intensity sound risked permanent hearing damage.

A multi-organization research program[9] 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 system effects, vestibular (inner ear) effects, and chest wall/lung tissue effects. Researchers found that low frequency sonar exposure could result in significant cavitations, hypothermia, 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 dB. 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 encephalopathy.[10]

History

Ancient inventors

According to legend, the concept of the "burning mirror" or death ray began with Archimedes 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 Roman 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 MythBusters television program). In particular, an experiment by students at MIT showed that a mirror-based weapon was at least possible, if not necessarily practical.[11]

Robert Watson-Watt

In 1935 the British Air Ministry asked Robert Watson-Watt of the Radio Research Station whether a "death ray" 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 radar 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 Feldberg, 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.[12]

Modern car engines are not mechanically, but electronically controlled. Disabling the electronics can indeed stop the engine. This has been implemented in OnStar, which has a remote control feature, but this is not a weapon. See also electromagnetic pulse (EMP), which is known for its engine-stopping effect, but is an undirected energy weapon.

Tesla

Nikola Tesla (1856–1943) was a noted inventor, scientist and electrical engineer. He invented Tesla coils, transformers, alternating current electrical generators and was the first early pioneer of radio 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.[13]

German World War II experimental weapons

In the later phases of World War II, Nazi Germany increasingly put its hopes on research into technologically revolutionary secret weapons, the Wunderwaffen.

Among the directed-energy weapons the Nazis investigated were X-Ray Beam Weapons developed under Heinz Schmellenmeier, Richard Gans and Fritz Houtermans. They built an electron accelerator called Rheotron (invented by Max Steenbeck at Siemens-Schuckert in the 1930s, these were later called Betatrons 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 Aschaffenburg. The Company Richert Seifert & Co from Hamburg delivered parts.[14]

The Third Reich further developed sonic weaponry, 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. President Ronald Reagan proposed the Strategic Defense Initiative (SDI) program, which was nicknamed Star Wars. It suggested that lasers, perhaps space-based X-ray lasers, could destroy ICBMs in flight. Though the strategic missile defense concept has continued to the present under the Missile Defense Agency, 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.[15]

Non-lethal weapons

Main article: 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."[16]

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."[17]

Some common bio-effects of non-lethal electromagnetic weapons include:

Interference with breathing poses the most significant, potentially lethal results.

Light and repetitive visual signals can induce epileptic seizures. Vection and motion sickness can also occur.

Cruise ships are known to use sonic weapons to drive off pirates.[18]

See also

Notes

  1. ^ Atomic Rocket: Space War: Weapons
  2. ^ "The Pentagon's Ray Gun". CBS News. 2008-06-01. http://www.cbsnews.com/stories/2008/02/29/60minutes/main3891865.shtml. Retrieved 2009-03-30. 
  3. ^ Raytheon focuses on non-lethal weapons,Andrew Johnson, (The Arizona Republic, 09-17-2009)
  4. ^ http://www.raytheon.com/capabilities/rtnwcm/groups/rms/documents/content/rtn_rms_ps_vigilanteagle_datas.pdf
  5. ^ http://www.baesystems.com/ProductsServices/BAE_GCSW_hpm_blackout.html
  6. ^ Magnus Karlsson (2009). ”Bofors HPM Blackout”. Artilleri-Tidskrift (2-2009): s. s 12-15. Retrieved 2010-01-04.
  7. ^ Google search
  8. ^ http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=7369133
  9. ^ Naval Submarine Medical Research Laboratory (Groton, Connecticut), Navy Experimental Diving Unit (Panama City, Florida), SCC San Diego, Navy Medical Research and Development Command (Bethesda, Maryland), Underwater Sound Reference Detachment of Naval Undersea Warfare Center (Orlando, Florida), Applied Research Laboratories: University of Texas at Austin, Applied Physics Laboratory: University of Washington, Institute for Sensory Research: Syracuse University, Georgia Institute of Technology, Emory University, Boston University, The University of Vermont, Applied Physics Laboratory, Johns Hopkins University, Jet Propulsion Laboratory, University of Rochester, University of Minnesota, University of Illinois system, Loyola University, State University of New York at Buffalo, New York
  10. ^ “Non-Lethal Swimmer Neutralization Study”; Applied Research Laboratories; The University of Texas at Austin; G2 Software Systems, Inc., San Diego; TECHNICAL DOCUMENT 3138; May 2002 Non-Lethal Swimmer Neutralization Study
  11. ^ Archimedes Death Ray: Idea Feasibility Testing
  12. ^ Jones, R.V.. Most Secret War: British Scientific Intelligence 1939–1945. Coronet. pp. 84,124. ISBN 0-340-24169-1. 
  13. ^ Seifer, Marc J., Wizard, the Life and Times of Nikola Tesla. ISBN (HC) pg. 454.
  14. ^ http://www.main-netz.de/nachrichten/region/aschaffenburg/aschaffenburg-land/land/art3986,883119
  15. ^ U.S. Senate - Committee on Veterans Affairs: Hearings - Gulf War Illnesses; Testimony to the Senate Veterans Affairs Committee; Meryl Nass, MD, Director of Pulmonary Rehabilitation, Mount Desert Island Hospital Bar Harbor, Maine; September 25, 2007 [1]
  16. ^ Human Effects Advisory Panel Program; presented to: NDIANon-Lethal Defense IV [2]
  17. ^ Non-Lethal Weaponry: From Tactical to Strategic Applications; Colonel Dennis B. Herbert, USMC (Ret.), program developer, Institute for Non-Lethal Defense Technologies at Pennsylvania State University; pg. 4 [3]
  18. ^ Smith, David (November 22, 2006). "Pirates shoot at Britons' cruise liner". The Guardian (London). http://www.guardian.co.uk/travel/2005/nov/06/travelnews.uknews.theobserver. 

References

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