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 on humans may be non - lethal or lethal . Aside from uses on people or as a potential missile defense , directed energy technology has also been shown to stop or disable moving cars , drones , jetskis and electronic devices such as mobile phones . The energy can come in various forms : Operational advantages . General . DEWs can be used discreetly without anyone knowing as radiation used in ranges such as RF ( Radio Frequency = 3 kHz to 300 GHz ) is invisible and can pass through walls . Examples of DEWs . DEWs tend to be categorised by the frequency in which they operate such as RF ( for radio frequency ) and Laser , or the way in which they operate . Microwave weapons . Although some devices are labelled as Microwave Weapons ; the microwave range is commonly defined as being between 300Mhz and 300Ghz which is within the RF range . Some examples of weapons which have been publicized by the military are as follows : General information on lasers . Lasers are often used for sighting , ranging and targeting for guns ; in these cases 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 laser s . 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 weapon s , such as dazzler s which are designed to temporarily blind or distract people or sensors . 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 . 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 . Other . Laser weapons could have several main advantages over conventional weaponry : Modern ballistic weapons commonly feature systems to counter many of the undesirable side - effects mentioned above . As such , laser weapons ' advantage over ballistics could end up more about elegance and cost . Problems and ethical considerations . 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 can yield an unacceptable delay between shots . These problems , which severely limit laser weapon practicality at present , might be offset by : Chemical laser s use energy from a suitable chemical reaction instead of electricity . 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 its own problems , and issues with cooling and overall inefficiency remain . These problems could 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 , as it would have the advantage of plentiful water for cooling . Blooming . Laser beams begin to cause plasma breakdown in the atmosphere at energy densities of around one megajoule per cubic centimetre . This effect , called " blooming , " causes the laser to defocus and disperse energy into the surrounding air . Blooming can be more severe if there is fog , smoke , or dust in the air . Techniques that may reduce these effects include : 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 : 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 . Masers . A 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 " . The lower - case usage arose from technological development having rendered the original denotation imprecise , because contemporary masers emit EM waves ( microwave and radio frequencies ) across a broader band of the electromagnetic spectrum ; thus , the physicist Charles H . Townes ' s suggested usage of " molecular " replacing " microwave " , for contemporary linguistic accuracy . In 1957 , when the optical coherent oscillator was first developed , it was denominated " optical maser " , but usually called laser ( Light Amplification by Stimulated Emission of Radiation ) , the acronym Gordon Gould established in 1957 . The dual noble gas of a masing medium which is nonpolar . Particle - beam weapons . Particle - beam weapons can use charged or neutral particles , and can be either endoatmospheric or exoatmospheric . Particle beam 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 : Plasma weapons . 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 . 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 . 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 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 cavitation s , 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 . 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 . 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 . Modern automobile 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 . It is an add - on to the electronics of the car . Because a car is operating on a closed system , it would be impossible to use an electronic means of disengaging an engine , short of electrocuting it via laser or pulse weaponry . See also electromagnetic pulse ( EMP ) , which is known for its engine - stopping effect , but is an undirected - energy weapon . Tesla . Nikola Tesla ( 1856 – 1943 ) , a noted inventor , scientist and electrical engineer , developed early high frequency technologies . 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 . 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 dish es pulse - detonated at roughly 44 Hz . This infrasound , magnified by the dish reflectors , caused vertigo and nausea at by vibrating the middle ear bones and shaking the cochlear fluid within the inner ear . At distances of , the sound wave s could act on organ tissues and fluids by repeatedly compressing and releasing compressive resistant organs such as the kidneys , spleen , and liver . ( It had little detectable effect on malleable organs such as the heart , stomach and intestine s . ) Lung tissue was affected at only the closest ranges as atmospheric air is highly compensable and only the blood rich alveoli resist compression . In practice , the weapon system was highly vulnerable to enemy fire . Rifle , bazooka and mortar rounds easily deformed the parabolic reflectors , rendering the wave amplification ineffective . In the later phases of World War II , Nazi Germany increasingly put its hopes on research into technologically revolutionary secret weapon s , the " Wunderwaffe n " . 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 Betatron 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 Aschaffenburg . The Company Richert Seifert & Co from Hamburg delivered parts . 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 laser s , 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 . However , Boeing has been somewhat successful with the Boeing YAL - 1 and Boeing NC - 135 , the first of which destroyed two missiles in February 2010 . Funding has been cut to both of the programs . 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 crowd control . Types and magnitudes of exposure to electromagnetic fields are unknown . Alleged tracking of Space Shuttle " Challenger " . The Soviets invested some effort in the development of ruby and carbon dioxide laser s as anti - ballistic missile systems , and later as a tracking and anti - satellite system . There are reports that the Terra - 3 complex at Sary Shagan was used on several occasions to temporarily " blind " US spy satellites in the IR range . It has been claimed that Russia made use of the lasers at the Terra - 3 site to target the Space Shuttle " Challenger " in 1984 . At the time , the Soviets were concerned that the shuttle was being used as a reconnaissance platform . On 10 October 1984 ( STS - 41 - G ) , the Terra - 3 tracking laser was allegedly aimed at " Challenger " as it passed over the facility . Early reports claimed that this was responsible for causing " malfunctions on the space shuttle and distress to the crew . " The United States filed a diplomatic protest about the incident . However , this story is comprehensively denied by the crew members of STS - 41 - G and knowledgeable members of the US intelligence community . Law enforcement . Dazzler s are devices used for temporarily blinding or stunning an attacker , or to stop a driver in a moving vehicle . Targets can also include mechanical sensors or aircraft . Dazzlers emit infrared or invisible light against various electronic sensors , and visible light against humans , when they are intended to cause no long - term damage to eyes . The emitters are usually lasers , making what is termed a " laser dazzler " . Most of the contemporary systems are man - portable , and operate in either the red ( a laser diode ) or green ( a diode - pumped solid - state laser , DPSS ) areas of the electromagnetic spectrum . Future . Currently , the technology is being considered for non - military use to protect Earth from asteroid s . 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 : 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 ( such as LRAD ) to drive off pirates .