See discussions, stats, and author profiles for this publication at: https://www.researchgate.

net/publication/334050459

Directed Energy Weapons

Conference Paper · November 2017

CITATIONS READS

2 13,689

2 authors:

Anna de Courcy Wheeler Maya Brehm

Article 36 Article 36
5 PUBLICATIONS 3 CITATIONS 19 PUBLICATIONS 100 CITATIONS

SEE PROFILE SEE PROFILE

All content following this page was uploaded by Maya Brehm on 27 June 2019.

The user has requested enhancement of the downloaded file.

 Directed Energy Weapons (DEW) have long captured military at-
DISCUSSION PAPER| NOVEMBER 2017 tention – and budgets – and are now on the cusp of technological
maturity. Whilst doubts remain over whether certain types can be
fully operationalized, recent tests of prototype DEW have made it
clear that this form of weaponry has moved beyond just a theoreti-
cal concept. As the underlying technology matures and is subject-
ed to testing outside of laboratories, it will likely attract increased
attention from militaries and governments seeking to establish
technical superiority over adversaries, including by developing
weaponry that can be used in space. Several modern militaries
have already invested heavily in developing the technology; many

Directed Energy Weapons others are likely to have an interest in acquiring it.

DEW can be broadly defined as systems that produce ‘a beam of

concentrated electromagnetic energy or atomic or subatomic parti-
cles’,1 which is used as a direct means to incapacitate, injure or kill
people, or to incapacitate, degrade, damage or destroy objects. Nota-
bly, this definition excludes sonic and ultrasonic weapons, which use
sound waves to affect a target rather than electromagnetic waves.
Discussion paper for the Convention on DEW currently take three primary forms:
Certain Conventional Weapons (CCW)
× lasers capable of shooting down planes and missiles, or of using
bright light to ‘dazzle’ or disorient people;
Geneva, November 2017 × weapons that use electromagnetic waves of other wavelengths,
including millimetre waves or microwaves, that can be directed
Article 36 is a UK-based not-for-profit organisation working to promote public against human or hardware targets;
scrutiny over the development and use of weapons.* × weapons using particle beams to disrupt or damage a target’s
molecular or atomic structure.
www.article36.org
info@article36.org
@Article36 Consideration of the current and anticipated development of these
weapons suggests several areas of concern:

× Certain DEW may have the potential to circumvent existing legal

restrictions and prohibitions on weapons, such as the prohibition
on blinding laser weapons, creating comparable effects to prohib-
ited systems but without falling within their technical definitions.
× Traditional interpretations of protective principles, including the
prohibition on causing superfluous injury or unnecessary suffering
to combatants, may be challenged by novel ways of inflicting phys-
ical and mental harm. Historically, systems that harm subjects
through non-kinetic means have often been considered an issue of
concern or as requiring special consideration.
× There appears to be little public data and considerable uncertain-
ty about the environmental and health effects of DEW.
× Some DEW are promoted for use in various settings and for di-
verse purposes, which risks further blurring the boundary between
law enforcement and war fighting, which traditionally have been
subject to different normative regimes.

Based on these concerns, High Contracting Parties to the Convention

on Certain Conventional Weapons (CCW) should:

× monitor research and development of DEW and assess their

potential to challenge existing restrictions and prohibitions on
weapons, or impact national and human security, peace and
international security, arms control and disarmament;
× ensure respect for the letter and the spirit of the CCW and its
protocols, reaffirm core values and long-standing principles these
instruments give expression to and assess the conformity of novel
*
This paper was written by Anna de Courcy Wheeler. mechanisms of harm with the prohibition on causing superfluous

1
 injury and unnecessary suffering, and the principle of distinction; mechanical impulse. Together, these properties can cause more
× reaffirm the prohibition on blinding laser weapons and assess extensive damage than when used alone.11 By heating a target, the
whether CCW Protocol IV provides adequate protection against beam can deform or melt a hole in it; if pulsed and at much greater
blinding in light of the risk to eyesight posed by developments in momentary intensities, a beam can cause vaporization, which in turn
laser technologies and the evolving understanding of blindness; delivers an impulse to the surface of a target,12 effectively transferring
× encourage transparency and integrate consideration of DEW in momentum to it and thereby damaging it through mechanical means.
ongoing work, including in relation to weapons reviews in line
with Article 36 of Additional Protocol I to the Geneva Conventions The technology of military lasers currently under development falls
(API), ensure that a precautionary approach is applied and that into three broad categories: chemical lasers; electric-powered and
assessments of environmental impact reflect the contemporary solid-state lasers, including optical fibre lasers; and free-electron
understanding of environmental law and protection. lasers, the newest and most complex.

× Chemical lasers are fuelled by a potentially toxic mix of chemicals

Current state of play that requires complex logistics to handle and transport, and which
carries significant environmental and health risks.13
Advances in a range of sciences and technological applications are
× Electric-powered and solid-state lasers14 are more stable and more
now feeding into significant progress in the development of lasers
easily transported, but are currently not very efficient as much
and other DEW.2 Yet there is no consensus on their utility or desirabil-
of the energy required to produce a stable laser beam is lost as
ity: for some, DEW will be at the forefront of a new wave of weaponry;
heat. Those working to further develop such lasers have struggled
others remain sceptical over both the desirability and the operational
to develop sufficient cooling mechanisms to counteract this,
or strategic utility of such weapons systems. Many, particularly policy
though progress is being made.
makers, have grown wary of what they perceive as a lack of delivery
× Free-electron lasers use a stream of electrons that passes through
despite billions of dollars of investment.3
alternating magnetic fields to generate megawatt laser beams.
They avoid both the difficulties of using chemical fuels (as in
Lasers chemical lasers) and the issue of heat generation (as in electric
and solid-state lasers), but they would be very big.
Long a staple of science fiction, lasers4 have captured the attention
of militaries and policy makers since Albert Einstein first theorized The recent advent of more portable and relatively cheap laser sys-
about the possibility of ‘stimulated emission’ in 1917.5 Now, several tems15 driven by developments in nanotechnology,16 battery power
decades after the first laser was demonstrated in 1960, advances in and optical fibres, has renewed enthusiasm for DEW broadly and
a wide range of science disciplines have allowed laser technology to laser weapons in particular. Lasers require large amounts of power
develop and be refined for both civilian and military use. to affect a target,17 but the necessary additional power generators
and sufficient cooling systems to counteract the thermal effects have
High-power lasers direct intensely focused beams of energy, and are traditionally taken up a considerable amount of space, space that
usually powered by a chemical fuel, electric power or a generated combat-ready vehicles do not easily provide. On the other hand,
stream of electrons.6 Over the past 20 years, their use has acceler- lasers are not only increasingly portable, but more fuel efficient than
ated in the commercial sector, where lasers are now routinely used they once were, and certainly less costly than their military alterna-
for tasks such as metal cutting and welding. Lasers are also used by tive, often a missile.18 This has been reflected in the advancement of
militaries and law enforcement agencies to designate targets, or in tests: the US Navy trialled its laser weapons system (LaWS) to shoot
rangefinders to determine distances. down a ScanEagle UAV in 2013 and, in November 2014, to target
small high-speed boats, marking the first successful demonstration of
An attempt to develop ‘battlefield’ or ‘tactical’ laser weapons re- the operational use of such a weapon. The defence ministries of the
sulted in the development of laser weapons for anti-personnel use UK and Russia have also reportedly confirmed that they are channel-
in the 1990s.7 Such laser weapons, which were designed to cause ling extensive funding towards the development of laser, electromag-
permanent blindness, were prohibited in 1995 under Protocol IV netic and plasma weapons.19
to the CCW8 before they were widely put to use. However, states
pressed ahead with the development of laser systems for use against
military hardware such as weapon platforms and vehicles, including
Microwave and millimetre-wave radiation technologies
unmanned aerial vehicles (UAVs or ‘drones’), electronic equipment,
Several militaries are already seeking to weaponize microwave
and for missile defence, as well as so-called ‘dazzlers’, which target
and millimetre-wave radiation20 technologies. Improvements in
electronic sensors with infrared or invisible light.9 They can also,
the underlying technology have enhanced the operational utility of
when designed to emit visible light, be used against humans to
electromagnetic weapons by making them more portable, improving
‘dazzle’, temporarily blind or disorient.10
the system’s power density (the amount of energy stored per unit
of volume), extending the range of the weapons and increasing the
Lasers have a number of effects on targets, which can be used to
power output.
military advantage. Their most basic effect is heating, though in most
lasers this is not sufficient to cause damage to hardware protect-
Such weapons can be used to disable electronic systems, including
ed by military armour. At lower intensities, lasers can be used to
those embedded in military hardware and equipped with tradition-
produce a targeted flash or continuous beam that temporarily blinds
al electromagnetic pulse shielding. They work by bombarding the
or ‘dazzles’. At higher intensities, they can create both heat and a
electronic systems that power or guide such military hardware with

2
energy pulses that cause them to overload and shut down. China, the difficulties of beam control have also curbed their current utility.
Russia and the US are all reported to be actively pursuing the use of According to one analysis, the ‘size, weight, power constraints and
this technology in their military arsenals.21 One Chinese microwave inherent complexity’ of neutral-particle beam weapons means that
weapon, which recently won China’s National Science and Technology they are unlikely to ‘see the light of day before 2025’.30
Progress Award, is reportedly portable enough to be transported by
standard military land and air vehicles.22 It is also reported that the Many of these challenges – including generating enough energy,
US has successfully tested one such weapon, CHAMP (the Count- difficulties of focus and control, high costs and lack of portability –
er-electronics High-powered Microwave Advanced Missile Project), an are shared across DEW. Key technical and financial barriers to their
air-launched cruise missile with a high-power microwave payload.23 military operationalization remain, but progress is rapidly being made
Other microwave systems have been developed for use against mis- towards overcoming these, facilitated not just by direct investment,
siles, improvised explosive devices (IEDs) and military vehicles. but also by significant advancements in a wide range of other
technologies, most notably energy-generating and energy-storage
Alternatively, weapons using millimetre waves (often, somewhat con- technology, nanotechnologies and materials sciences. At the same
fusingly, called ‘microwave weapons’ in news reports) can be used time, other complementary technologies – for example, advanced
against people by heating the skin to intolerably painful tempera- image recognition that gives finer details of a target, thereby enabling
tures. Such weapons are envisaged for use in crowd control and dis- the placement of a beam on the target’s most vulnerable point – are
persal, as well as at checkpoints and for perimeter security, but could increasing the combat utility of weapons that would rely on energy
have a wide range of applications. China has already developed such beams.
a weapon, commonly known as Poly WB-1, which will reportedly be
used by its navy.24 The best-known example, however, remains the Adverse effects and risks
US Active Denial System, a millimetre-wave source that produces an
intense burning sensation in the skin, but leaves no visible mark. It DEW have not yet been widely used in conflict or other settings, but
was reportedly deployed in Afghanistan, but later withdrawn due to there is some research available on their effects – from accidents,
practical difficulties and concerns over how the use of the weapon worker protection and published military investigations.31 DEW by
might be perceived.25 their nature operate with varying intensities, and the duration of expo-
sure and other physical and operational factors can produce a wide
Particle beams range of effects, from barely noticeable to deadly. Their technical
characteristics, however, do raise a number of concerns over human
During the Cold War, the US and USSR explored particle beam physical and psychological welfare, as well as potential damage to
weapons for use both in the atmosphere and in space, but eventually civilian infrastructure.
abandoned the research as unfeasible for military application.26 Par-
ticle beam weapons are closer to conventional kinetic weapons than The technologies behind DEW can be used to produce damaging
laser or electromagnetic wave weapons in that they rely on kinetic physical effects, both in the short term and potentially in the long
energy. But instead of projectiles, they fire atomic or sub-atomic parti- term, where questions remain over the long-term negative health
cles at a target with the aim of disrupting or destroying that target’s effects of exposure and the effects of such exposure on individuals
molecular or atomic structure. Essentially, they rapidly heat the with pre-existing health conditions. In terms of immediate effects,
target’s molecules and/or atoms to the point that the target material lasers can produce anything from a glare or slight warming of the
explodes; in their effects, they have been likened to lightning bolts.27 skin to blindness and severe skin burns.32 Pulsed high-power lasers
These weapons can be divided into two types: weapons that use par- can produce plasma in front of a target, which then creates a blast
ticles (for example, electrons or protons) that possess an electrical wave with subsequent blunt trauma.33 Even low-power laser weap-
charge, which are suited for use within Earth’s atmosphere, and neu- ons that are intended to temporarily blind or ‘dazzle’ can cause eye
tral-particle beam weapons, made up of particles that are electrically damage if used for extended periods or if the target is too close.34
neutral, which are better suited for use in space. Because of the way Electromagnetic radiation weapons can penetrate clothing to heat a
in which particle beams interact with a target, applying extra layers of person’s skin, causing pain and potentially severe burns;35 particle
protective material is unlikely to limit the damage inflicted. beam weapons can be expected to produce significant and potential-
ly deadly burns as well as other injuries, including some consistent
The technology behind them – particle accelerators28 – has been with ionizing radiation.36 The one known instance of injury caused
used for scientific research, including as colliders in the field of by a single hit from a higher-intensity particle accelerator resulted
particle physics, and in a range of industrial and civilian applications in the beam burning a hole directly through a physicist’s skin, skull
including medical treatment. As yet, however, they have not been and brain. Though he survived through luck (the beam missed crucial
extensively developed as a weapons technology due to a number parts of his brain), longer-term effects – many of them consistent
of technical challenges that make them impractical, not least the with the radiation side effects seen in, for example, cancer treat-
lack of weapon-grade and portable accelerators. To work in Earth’s ments – included fatigue, loss of hearing, seizures and partial facial
atmosphere, they would need an extremely large power supply. To paralysis.37
work in space, they would require the ability to very precisely control
the characteristics of the beam generated. Charged-particle beam There is little publicly available research on the anticipated psycho-
weapons using current technology would also need to be large logical effects of DEW. They are likely to vary depending on individual
fixed installations, making them vulnerable to attack and rendering vulnerability and state of health, the nature of the target and the
them of limited military use.29 Thermal and electrostatic ‘blooming’ context – for example, whether such weapons are used for policing
(a process by which the beam becomes distorted or diffused) and a crowd in the open, in a confined space or in a battlefield situation

3
– and the degree to which those people affected by the weapons law enforcement, both during and outside of armed conflict, and
understand what is happening and have training in how to anticipate irrespective of whether the weapons are used by police or military
and counter their effects. Electromagnetic radiation weapons have, actors. Similarly, according to IHL – the primary legal regime that
to date, reportedly only been tested on trained soldiers; how civilians would govern the use of DEW for the conduct of hostilities – the right
will react to the sensation of intolerable heating of the skin or to the of the parties to the conflict to choose methods or means of warfare
disorienting effect of ‘dazzler’ lasers is unknown, but it is not unlikely is not unlimited.43 Under Article 36 of API, states have an obligation
that the use of such weapons against civilians or forces unfamiliar to assess all new weapons, means or methods of warfare to see
with them would cause significant panic and perhaps subsequent whether their employment would fall foul of their legal obligations in
injury. It is also likely that the use of invisible ‘rays’ as a mechanism some or all circumstances.44
for causing harm would raise ethical and political concerns in some
societies. There is a wide range of IHL provisions that could act to bar or limit
the use of DEW. One form of DEW – blinding laser weapons – has
DEW, and particularly those that use electromagnetic pulse tech- already been expressly prohibited by Protocol IV to the CCW.45 That
nology to overload or disrupt electrical systems and high-technology instrument also requires that all feasible precautions, including prac-
microcircuits, also present risks beyond those of direct physical and tical measures, be taken in the employment of other laser systems
psychological harm. As critical civilian infrastructure increasingly to avoid permanent blindness to unenhanced vision,46 and a strong
relies on connected electronic and satellite technology, the impact of argument can be made that the Protocol in effect also prohibits
an electromagnetic pulse (EMP) device (also known as an ‘E-bomb’) the deliberate use of other laser systems to blind.47 However, the
has the potential to cause propagating failures in power, transport definition of ‘permanent blindness’ used in the Protocol may not
and communications networks.38 accord with a modern understanding of ‘visual impairment’.48 It was
already criticized as unscientific at the time of adoption, and states
parties foresaw that it could be reconsidered in the future, taking into
Governance and regulation account scientific and technological developments.49
DEW are not authoritatively defined under international law, nor are
Despite claims regarding the accuracy of DEW, questions remain
they currently on the agenda of any existing multilateral mechanism.
around the ability to target certain DEW at a specific military objec-
Nevertheless, there are a number of legal regimes that would apply
tive,50 in compliance with the IHL rule of distinction and the prohi-
to DEW. These range from national civilian-use regulations and guide-
bition of indiscriminate attacks.51 Potential effects such as burning,
lines to international humanitarian law (IHL) and human rights law
eye damage or radiation sickness may raise concerns under the
that would constrain or preclude their use in certain situations.
prohibition of causing superfluous injury or unnecessary suffering.52
Such non-kinetic mechanisms of harm have historically provided
The prospect of DEW raises questions under several bodies of
grounds for concern regarding the acceptability of weapons. It is also
international law, most notably those that place restrictions on the
questionable whether the intentional and unintended harm occa-
use of force. Some DEW are classified as ‘non-lethal’ or ‘less-lethal’
sioned by the use of a DEW can be properly assessed, a requirement
weapons, with proponents setting them apart from ‘lethal’ weapons.39
for compliance with the rules on proportionality and on precautions
In the civilian sphere, the sale, power and use of the technologies
in attack.53
behind DEW – lasers, microwave beams and particle accelerators
(and, in particular, ionizing radiation) – are all regulated to varying
International environmental law may also be implicated in the use
degrees,40 suggesting that their potential to cause damage to human
of certain DEW. Protection of the environment during armed conflict
health has already been recognized under domestic legal regimes.
is increasingly emphasized as technological developments in new
weaponry present new threats to the natural world.54 In May 2016,
Human rights concerns over DEW primarily relate to the rights to life,
the UN Environment Assembly agreed a resolution stressing the
health, freedom of assembly (particularly in the case of weapons
importance of environmental protections during armed conflict and
that could be used for crowd control such as millimetre and micro-
urging states to comply with IHL environmental protections. Chemical
wave weapons), and the prohibition on cruel, inhuman or degrading
lasers in particular may raise concerns under environmental law, due
treatment. Certain DEW are designed to act silently and invisibly –
to their use of a toxic mix of chemicals to power the beam – chemi-
such as millimetre-wave weapons, which cause severe pain without
cals that present a significant hazard in the case of an accident or if
necessarily leaving visible marks or physical evidence of their use
left abandoned.
– making their abuse easy to conceal and raising concerns about
accountability for harm done and the availability of an effective rem-
DEW have been envisioned for use in outer space as well as within
edy to victims. Depending on the width of beam used, they also risk
Earth’s atmosphere, primarily as a form of directly attacking space
adversely affecting bystanders.41
assets such as satellites. The use of weapons in outer space is
regulated by the 1967 Outer Space Treaty, which states that all use
According to the 1990 UN Basic Principles on the Use of Force and
of outer space must be ‘in accordance with international law’. DEW
Firearms by Law Enforcement Officials (BPUFF), an authoritative
designed to deliver an electromagnetic blast or to target satellites
statement of international rules governing use of force in law enforce-
raise concerns due to their potential impact on civilian infrastructure.
ment, ‘the development and deployment of non-lethal incapacitating
Important questions remain about how the restrictions and prohibi-
weapons should be carefully evaluated in order to minimize the risk
tions that could apply to DEW under, for example, IHL, would apply to
of endangering uninvolved persons, and the use of such weapons
their use in outer space.
should be carefully controlled’.42 This applies to the use of DEW for

4
Given the potential adverse effects of DEW and the uncertainties prohibits the use of blinding laser weapons as a means or method of warfare, as well
around their further development, a precautionary orientation, as their transfer to any state or non-state actor.
9 Russia’s Sokol Eshelon project is reportedly working to develop a laser to blind the
both politically and under international law, is warranted. Such an sensors of an enemy satellite (D. Cenciotti, ‘Russia Has Completed Ground Tests of Its
orientation should seek to address the questions and concerns that High-Energy Airborne Combat Laser’, Business Insider, 5 October 2016, https://www.
arise relating to the established norms and principles of IHL and businessinsider.com/russia-high-energy-airborne-combat-laser-system-2016-10?r=UK).
international human rights law, as well as other bodies of law such as 10 One example is the PHaSR (Personnel Halting and Simulation Response)
developed by the US Air Force and designed to stun or ‘dazzle’ a target (E. D. Blaylock,
environmental and space law. As state use of DEW in military and do- ‘New Technology “Dazzles” Aggressors’, U.S. Air Force, 2 November 2005, https://
mestic law enforcement operations increases, prompt action will be archive.is/20120721195102/http:/www.af.mil/news/story.asp?storyID=123012699).
needed to ensure the risks they present to human health and dignity 11 P. E. Nielsen, Effects of Directed Energy Weapons, 2009, p. 170.
are adequately recognized, assessed and protected against. 12 ‘Mechanical effects result when momentum is transferred to a target by vapor
shooting from it. In effect, the vapor serves as a small jet, and exerts a reaction force
back on the target’ (ibid, p. 175).
Whether combat-ready DEW systems are a fast-approaching reality or 13 D. Pudo and J. Galuga, ‘High Energy Laser Weapon Systems: Evolution, Analysis
remain a more distant proposition, these advances will need careful and Perspectives’, 17(3) Canadian Military Journal (2017), http://www.journal.forces.
and comprehensive scrutiny in order to understand their potential hu- gc.ca/Vol17/no3/PDF/CMJ173Ep53.pdf.
14 These include optical fibre lasers like the US Navy’s LaWS.
manitarian and other impacts. Yet they are not currently being actively 15 Solid-state lasers use rods, slabs or discs of crystal to produce the beam,
considered on the agenda of any existing international mechanism. whereas fibre lasers use thin optical fibres that are lightweight and more compact
(A. Extance, ‘Military Technology: Laser Weapons Get Real’, 521(7553) Nature
(May 2015), https://www.nature.com/news/military-technology-laser-weapons-get-
real-1.17613).
16 H. Nasu, ‘The Future of Nanotechnology in Warfare’, The Global Journal, 4 July
2013, http://www.theglobaljournal.net/article/view/1132/.
17 E.g., to destroy an anti-ship cruise missile, a laser would require a beam
of 500 kW and demand megawatts of power (A. Robinson, ‘Directed Energy
Weapons: Will They Ever Be Ready?’, National Defense, 1 July 2015, http://www.
nationaldefensemagazine.org/articles/2015/7/1/2015july-directed-energy-weapons-
END NOTES will-they-ever-be-ready).
18 A recent report set the ‘cost per kill’ at about $30 for a ‘pre-prototype’ laser-
1 Joint Publication 1-02, 8 November 2010, p. 68, https://fas.org/irp/doddir/dod/ equipped vehicle designed to target drones and missiles (J. Kester, ‘Army, Defense
jp1_02.pdf. Companies Making Renewed Push for Laser Weapons’, Foreign Policy, 12 Oct 2017,
2 These include: nanotechnology, materials science, battery and energy delivery, https://foreignpolicy.com/2017/10/12/army-defense-companies-making-renewed-
greater computing power, better understanding of the variables that influence the use push-for-laser-weapons/). See also UK Defence Science and Technology Laboratory,
of DEW in Earth’s atmosphere and adaptive optics. ‘Dragonfire: Laser Directed Energy Weapons’, press release, 13 September 2017,
3 J. D. Ellis, Directed-Energy Weapons: Promise and Prospects, Center for a New https://www.gov.uk/government/news/dragonfire-laser-directed-energy-weapons.
American Security, April 2015, p. 4, https://www.cnas.org/publications/reports/ 19 T. Batchelor, ‘Russia Developing Laser, Electromagnetic and Plasma Weapons,
directed-energy-weapons-promise-and-prospects. Though fully developed and fielded Kremlin Says’, Independent, 22 January 2017, https://www.independent.co.uk/
DEW offer a significant reduction in costs when compared to their kinetic counterparts news/world/europe/russia-laser-electromagnetic-plasma-weapons-military-
– a shot from a laser is significantly cheaper than a missile – their development kremlin-a7540716.html. The UK is reportedly aiming to develop a ship-mounted
thus far has proven incredibly costly, and significantly more investment would be laser cannon by 2020 (E. MacAskill, ‘Royal Navy Aims to Put Laser Weapon on
needed in order to make them fully operational and combat-ready. It is unclear to Ships by 2020’, The Guardian, 15 September 2015, https://www.theguardian.com/
what degree states will see these costs as a worthwhile investment. According to uk-news/2015/sep/15/royal-navy-death-ray-laser-cannon-ships-2020; UK Defence
an estimate from the US Office of the Assistant Secretary of Defense for Research Science and Technology Laboratory, ‘Dragonfire’.
and Engineering/Research Directorate, the US Department of Defense has, since 20 Microwaves are a band of radio frequencies in the electromagnetic spectrum
1960, invested over $6 billion in directed energy science and technology initiatives ranging in frequency from 300 MHz to 300 GHz with a wavelength ranging from 100 cm
(Center for Strategic and Budgetary Assessments, Changing the Game: The Promise of to 0.1 cm. This includes millimetre waves, electromagnetic radiation in the frequency
Directed-Energy Weapons, 2012, p.48, https://csbaonline.org/uploads/documents/ range of 30 GHz to 300 GHz with a wavelength in the 10 mm to 1 mm range.
CSBA_ChangingTheGame_ereader.pdf). In January 2017, the UK reportedly awarded a 21 B. Gertz, ‘Report: China Building Electromagnetic Pulse Weapons for Use Against
£30 million contract to a consortium of European defence firms to produce a prototype U.S. Carriers’, The Washington Times, 21 July 2011, https://www.washingtontimes.
laser weapon (P. Rincon, ‘UK Military to Build Prototype Laser Weapon’, BBC News, 5 com/news/2011/jul/21/beijing-develops-radiation-weapons/; A. Withnall, ‘Russia
January 2017, https://www.bbc.co.uk/news/science-environment-38510344). The US Demonstrates First “Microwave Gun” That Can Disable Drones and Missiles From up to
2017 Defense Bill also reportedly authorized some $328 million for the development Six Miles Away at Army-2015’, Independent, 16 June 2016, https://www.independent.
and procurement of directed energy weapons (S. Snow, ‘Congress OKs More Money, co.uk/news/world/europe/russia-demonstrates-its-first-microwave-gun-that-can-
Gets Serious About Laser Weapons in Defense Bill’, Military Times, 28 December 2016 disable-drones-and-missiles-from-up-to-six-10323243.html.
https://www.militarytimes.com/news/pentagon-congress/2016/12/28/congress-oks- 22 J. Lin and P. W. Singer, ‘China’s New Microwave Weapon Can Disable Missiles
more-money-gets-serious-about-laser-weapons-in-defense-bill/). Full text of bill available and Paralyze Tanks’, Popular Science, 26 January 2017, https://www.popsci.com/
at https://www.govtrack.us/congress/bills/114/s2943/text. china-microwave-weapon-electronic-warfare.
4 The term ‘laser’ was originally an acronym for Light Amplification and Stimulated 23 Boeing, ‘CHAMP – Lights Out’, 22 October 2012, http://www.boeing.com/
Emission of Radiation. features/2012/10/bds-champ-10-22-12.page.
5 ‘Einstein Predicts Stimulated Emission’, 14(8) APS News, (August/September 24 A. Griffin, ‘China Reveals Long-Range Heat Ray Gun’, Independent, 15 December
2005), https://www.aps.org/publications/apsnews/200508/history.cfm. 2014, https://www.independent.co.uk/life-style/gadgets-and-tech/news/china-reveals-
6 Chemical lasers have historically succeeded in producing megawatt-level outputs, long-range-heat-ray-gun-9925713.html.
but they are unwieldy and logistically difficult to transport and use. In recent decades, 25 B. Buch and K. Mitchell, ‘The Active Denial System: Obstacles and Promise’,
there has been a shift in focus to solid-state lasers, which are often more portable and Policy White Paper, Global Research Institute, William & Mary, April 2013, p. 22,
fuel efficient; they are, rather, in the kilowatts to tens-of-kilowatts class. More recently, https://www.wm.edu/offices/global-research/projects/pips/_documents/pips/2011-
free-electron lasers – usually very large and immobile – have garnered interest due 2012/active_denial_system.pdf.
to their ability to circumvent some of the technical challenges that have hampered 26 A. Kochems and A. Gudgel, ‘The Viability of Directed-Energy Weapons’, The
attempts to operationalize other types of lasers. Heritage Foundation, 28 April 2006, https://www.heritage.org/node/16798/print-
7 In 1995, Human Rights Watch (HRW) reported that the US, China, Russia, Israel display.
and several European states were developing blinding laser weapons (HRW, United 27 R. M. Roberds, ‘Introducing the Particle-Beam Weapon’, Air University Review,
States: U.S. Blinding Laser Weapons, Human Rights Watch Arms Project, https://www. July–August 1984, https://www.bibliotecapleyades.net/scalar_tech/devvision/
hrw.org/reports/1995/Us2.htm. devvission-appendix-j.pdf.
8 Protocol IV to the 1980 Convention on Certain Conventional Weapons (CCW) 28 The best-known use of a particle accelerator is in the Large Hadron Collider at

5
CERN, which aimed to create Higgs Boson particles in order to study them. 49 Final Declaration of the Review Conference, Review Conference of the States
29 A. K. Maini, ‘Directed Energy Weapons: Particle Beam Weapons’, Electronicsforu. Parties to the Convention on Prohibitions or Restrictions on the Use of Certain
com, 12 August 2016, https://electronicsforu.com/market-verticals/aerospace- Conventional Weapons which may be Deemed to be Excessively Injurious or to Have
defence/directed-energy-weapons-particle-beam. Indiscriminate Effects, Final Report, UN doc CCW/CONF.I/16(Part I), Annex C, 1996.
30 Ibid. For more information, see ‘Blinding Laser Weapons’, Weapons Law Encyclopedia,
31 See J. Altmann, Millimetre Waves, Lasers, Acoustics for Non-Lethal Weapons? http://www.weaponslaw.org/weapons/blinding-laser-weapons.
Physics Analyses and Inferences, Forschung DSF no 16, Deutsche Stiftung 50 E.g., atmospheric conditions can impact beam quality and, in turn, the ability
Friedensforschung, 2008, https://www.ssoar.info/ssoar/bitstream/handle/ of militaries to effectively operate DEW. This is particularly noticeable in laser beams,
document/26039/ssoar-2008-altmann-millimetre_waves.pdf?sequence=1&isAllowed where the air turns to plasma as the beam moves through it, causing the beam to lose
=y&lnkname=ssoar-2008-altmann-millimetre_waves.pdf. focus – so-called ‘blooming’. To hit targets at a great distance, the quality of the beam
32 B. Anderberg and M. L. Wolbarsht, Laser Weapons: The Dawn of a New Military generated will need to be significantly greater than that needed for current industrial
Age, 2013, p. 81. uses. The difficulty in sufficiently concentrating and targeting the beam, taking account
33 N. Davison, ‘Non-Lethal’ Weapons, 2009, p. 157. of atmospheric variations, raises significant concerns over military effectiveness and
34 W. Knight, ‘US Military Sets PHASRs to Stun’, New Scientist, 7 November 2005, harm to civilians. See, e.g., P. Sprangle et al, High-Power Lasers for Directed-Energy
https://www.newscientist.com/article/dn8275-us-military-sets-laser-phasrs-to-stun/. Applications, 54(31) Applied Optics (2015). Complex and challenging operational
35 Altmann, Millimetre Waves, Lasers, Acoustics for Non-Lethal Weapons? p. 18. environments can also be expected to exacerbate the inherent difficulties in the
For an independent review of the health effects of the Active Denial System (ADS) operation of DEW, as well as render more logistically difficult their maintenance (D. H.
in particular, see also J. M. Kenny et al, A Narrative Summary and Independent Titterton, Military Laser Technology and Systems, 2015, pp. 60–61.
Assessment of the Active Denial System, Penn State Applied Research Laboratory, 51 Art 51(4), API; ICRC, Customary IHL study, Rules 11 and 71.
2008, https://jnlwp.defense.gov/Portals/50/Documents/Future_Non-Lethal_ 52 Art 35(2) API; ICRC, Customary IHL study, Rule 70.
Weapons/HEAP.pdf. 53 Arts 51(5)(b) and 57(2)(a)(iii), API; ICRC, Customary IHL study, Rules 14, 15.
36 Theoretical effects of particle beam weapons are largely drawn from the known 54 See the International Law Commission’s draft principles on the protection
side effects of civilian-use particle beams. Particle accelerators and beams are used of the environment in relation to armed conflict, UN doc A/71/10, http://legal.
in radiotherapy as a medical treatment; known side effects in the short and long term un.org/docs/?path=../ilc/reports/2016/english/chp10.pdf&lang=EFSRAC; UN
vary depending upon the area of body being treated, but usually include skin damage Environment Programme, Protecting the Environment During Armed Conflict: An
(including radiation burns) and tiredness. Inventory and Analysis of International Law, 2009, https://www.un.org/zh/events/
37 In 1978, Russian scientist Anatoli Petrovich Bugorski accidentally put his head environmentconflictday/pdfs/int_law.pdf.
in the path of a Soviet particle accelerator whilst working as a researcher at the
Institute for High Energy Physics (J. Frolich, ‘What Happens if You Stick Your Head
in a Particle Accelerator?’, The Atlantic, 12 January 2017, https://www.theatlantic.
com/science/archive/2017/01/what-happens-when-you-stick-your-head-in-a-particle-
accelerator/512927/; M. Gessen, ‘The Future Ruins of the Nuclear Age’, Wired, 1
December 1997, https://www.wired.com/1997/12/science-2/).
38 A report by the US Commission established to assess the threat posed by an
EMP attack concluded that the US would suffer ‘long-term, catastrophic consequences’
due to societal dependence on the electrical power system and overall vulnerability to
attack. EMP Commission, Report of the Commission to Assess the Threat to the United
States from Electromagnetic Pulse (EMP) Attack, April 2008, https://apps.dtic.mil/
dtic/tr/fulltext/u2/a484672.pdf.
39 Both enthusiasm for and concerns over DEW have fallen under a larger debate
about the viability and place of ‘non-lethal’ weapons in both domestic policing and
situations of armed conflict, as well as the appropriate forms of regulation and legal
redress. Some proponents initially suggested that existing international law be modified
or discarded with regard to these weapons; opponents countered by insisting they must
comply with existing international law. For an overview, see D. P. Fidler, ‘The Meaning
of Moscow: “Non-Lethal” Weapons and International Law in the 21st Century’, 87(859)
International Review of the Red Cross (September 2005), https://www.icrc.org/
en/doc/assets/files/other/irrc_859_fidler.pdf; N. Lewer and M. Davison, ‘Bradford
Non-Lethal Weapons Research Project: Research Report No. 7’, University of Bradford,
May 2005, https://bradscholars.brad.ac.uk/bitstream/handle/10454/3999/
BNLWRPResearchReportNo7_May05.pdf?sequence=1.
40 E.g., in the US, it is illegal under the FAA Modernization and Reform Act (2012)
to shine a laser beam at or in the flight path of an aircraft; several states have set out
varying classes of laser products with accompanying safety standards; and products
emitting electronic radiation, including microwaves, are similarly regulated to eliminate
or minimize the risks of exposure.
41 The US ADS uses 1.5 m-wide beams of millimetre waves that range up to 1000
ft. It is unclear if this width is variable, or if it is adhered to in other millimetre-wave
systems (Non-Lethal Weapons Program, US Department of Defense, ‘Active Denial
System FAQs’, https://jnlwp.defense.gov/About/Frequently-Asked-Questions/Active-
Denial-System-FAQs/.
42 Principle 3, 1990 Basic Principles on the Use of Force and Firearms by Law
Enforcement Officials.
43 Art 35(1), API.
44 Art 36, API.
45 Protocol on Blinding Laser Weapons (1995), annexed to the framework
Convention on Prohibitions or Restrictions on the Use of Certain Conventional Weapons
(CCW). The prohibition is considered by the International Committee of the Red Cross
(ICRC) to be a norm of customary international law applicable in both international
and non-international armed conflicts (ICRC, Customary IHL study, Rule 86).
46 Art 2, 1995 CCW Protocol IV.
47 ICRC, Customary IHL study, Rule 86.
48 See World Health Organization, ‘Change the Definition of Blindness’, International
Classification of Diseases Updated and Revision Platform, https://www.who.int/
blindness/Change%20the%20Definition%20of%20Blindness.pdf?ua=1. www.article36.org
6

View publication stats