Changing The Game: Role of Directed Energy Weapons in Modern Warfare

28 January, 2023, would-in all practicalities-be noted as a cursed day in India’s aviation history as we witnessed three tragic aircraft crashes on the same day. While a board of enquiry has been set up by the Indian Air Force (IAF) to ascertain the cause of the mid-air crash between a Mirage 2000 and Su30, the undeniably intriguing part is that the debris fell hundreds of kilometres apart between Morena in Madhya Pradesh and Paharpur near Rajasthan. The third aircraft, a chartered one, crashed in Rajasthan’s Bharatpur.

In this regard, without making any speculation, it is perhaps imperative to discuss a pertinent and state-of-the-art, invisible technological weapon system of deadly precision that must also be taken into account by the investigating team of experts.

The concept of the Directed Energy Weapon (DEW) may have originated as early as 212 BC in Greece when Archimedes used polished mirrors to direct sunlight on the sails of Roman ships while defending the city of Syracuse. It was not until 1890 that HG Wells resurrected this concept in his book The War of the Worlds. And taking a leaf out of history, on 23 May, 1983, Ronald Reagan, the United States President, urged the development of a system that could intercept and destroy strategic ballistic missiles before these could reach the US soil or that of its allies.

In the near future, the DEW is envisaged to not only replace nuclear weapons but also make them look like bows and arrows with its gigantic technological superiority.

What are Directed Energy Weapons?

The term Directed Energy Weapon is used as a catch-all, to encapsulate a number of different technologies under one umbrella. These technologies are all at different levels of maturity, therefore talking about DEWs as a whole omits important nuances between the different types. There are three main systems which come under this umbrella term:

• Laser (Light Amplification by Stimulated Emission of Radiation)-based systems: Different types of lasers exist, of which chemical, solid-state and free-electron lasers are the most relevant. Despite being invented in the 1960s, the main obstacle to laser weapons has been the power required. Out of the different laser types, chemical lasers are the most mature. However, chemical lasers suffer from a number of impracticalities, including the fact that they use hazardous substances. Free-electron lasers are a more recent discovery and therefore, the least developed for weapon use. The laser weapons beginning to be deployed are solid-state (fibre) lasers. A laser can be used for two types of attack, thermal and impulse. In a thermal kill, the target is destroyed by a long dwell time of the laser and burning through it. On the other hand, if a very high-power laser pulse is used, it vapourises a small layer of the target skin and its surrounding air. These super-heated gases expand explosively, sending a shock wave into the target. Such a shock wave can destroy the skin and is known as impulse kill. It is a device that produces an intense, narrow beam of electromagnetic radiation which is capable of destroying a missile by damaging the skin or outer casing of the missile. The feature that makes a laser particularly attractive for the destruction of space systems is its potential to deliver a narrow beam, at a great distance, at the speed of light. This makes it faster than any kinetic energy weapon, by over a thousand times.
• Radio frequency systems: This category includes high-powered microwaves as well as millimetre waves. These types of systems are more technologically mature than laser-based systems and are already in operational use.
• Particle beam systems: Particle beam systems are the least mature of the three types of DEW; these systems, unlike the others, fire atomic and sub-atomic particles. Particle beam systems would emit either charged or neutral particles. Neutral particle beam systems hold particular interest, given these could be used outside of the atmosphere. A particle beam could bore a hole in the outer shell of a missile, a satellite or an aircraft and cause serious damage to electronics inside or explode the high explosives trigger of a nuclear weapon.

There are two types of Particle Beam Weapons (PBW). Charged particle beam weapon and neutral beam weapon. The charged particle weapons are for use within the atmosphere (endo-atmospheric) and the neutral particle beam weapons are used in space (exo-atmospheric). Both these weapon systems have different characteristics.

The fire control, procurement and tracking system of PBW must acquire and track the target, point the weapon at the target, fire the beam at the appropriate time and assess target damage. The miss distance has to be calculated and correction has to be carried out on time.

Advantages of PBW

• Beam Velocity- Being the speed of light (186,000 miles/sec), computing and the aim point for a moving target like an incoming missile become simpler. It would be difficult for the target to carry out any evasive manoeuvre.

• Beam Dwell Time- In an endo-atmospheric weapon, the target can be destroyed instantly provided the beam is held for a short period.

• Rapid Aim Capability- Because of its high velocity, the beam can be aimed at a number of targets in a very short range of time, by means of a magnetic field. Varying the current would change the magnetic field intensity, which could deflect the particle beam.

• Beam Penetration- Sub-atomic particles can penetrate a target. It is not restricted to surface effects as in the case of laser. It could damage the internal components of the target and even cause an explosion by implanting a massive quantity of energy. It would be nearly impossible to defend the target against such an attack. No amount of target hardening will have any effect.

• All Weather Capability- PBW has an added advantage over the laser. It has an all-weather capability. A laser beam can get degraded if there is fog, cloud or rain but it does not affect the PBW. In the atmosphere, as the particle beam travels, it produces an ionised channel which tends to keep the beam together and does not allow it to disperse.

What effect can DEWs achieve?

These systems are used in different circumstances and therefore, lead to different effects, which can be either lethal or non-lethal.

Lasers, particularly high-power ones and particle beam systems, can lead to the disruption and destruction of equipment, whereas low-power lasers can mainly dazzle systems, such as sensors, including those on satellites. High-powered microwaves can degrade and damage electronics, and as such can be used to counter threats from uncrewed aerial systems. But they could also be used to disrupt a wide range of electronics, from smartphones and motors to command posts. Finally, millimetre waves can be used as an anti-personnel area denial weapon; while not lethal, this system can produce a burning sensation on the skin.

While low-powered lasers and radio frequency-based systems are much more frequently used in the field, high-powered lasers are beginning to reach the technological maturity required to be used operationally, whereas particle-beam weapons remain far from that point.

DEWs are of increasing concern given their low operational cost per shot, their use of shots that travel much faster than those from conventional weapons and are unaffected by gravity, and their ability to launch silent and invisible attacks. Additionally, radio frequency attacks, in particular from high-powered microwaves, can be hard to attribute. While DEWs would not replace conventional weapons, they could – and to some extent already can – complement existing capabilities.

A number of countries in the Asia-Pacific region are caught up in the global hypersonic and directed-energy weapons race, with these regional powers having either developed or publicly stated intentions to develop such technology.

India’s research and development-oriented work on DEWs is a classified subject matter. Unsurprisingly, China, that is India’s primary security concern-being the undeniably expansionist adversary-is one of those countries that is focused on both fields. It is widely acknowledged to be the leader in the field of the hypersonic weapon system, having already fielded such weapons in the form of the DF-17 Hypersonic Glide Vehicle (HGV).

The DF-17 HGV made its first public appearance at a military parade held in China’s capital Beijing in late 2019. The weapon appears to use a standard ballistic missile booster in its first stage for the initial boost of a glide vehicle, which is used to attack a target following re-entry. The DF-17s at the parade were mounted on a wheeled, five-axle transporter-erector-launcher. This makes the system road-mobile like much of the ballistic missile arsenal of China’s People’s Liberation Army (PLA). This could potentially complicate any attempt by an adversary to strike the systems before launch.

The US government sources have said that China carried out several tests of HGVs, including the DF-17, since 2014. The DF-17 is the first system of its type known to be operational in the world, although several other nations including the US are developing similar systems.

In addition, China is also believed to be developing an air-launched HGV, with a video briefly posted on Chinese social media in October   2020 showing PLA Air Force Xi’an H-6N bomber, landing at an air base, carrying what appeared to be a boost-glide HGV — or at least a mock-up used for carriage and other flight tests. Pentagon officials had long suspected that China was developing an air-launched ballistic missile for carriage onboard H-6 bombers, although specific details were unknown until the emergence of the video. It’s still unclear, however, if this air-launched weapon is the one referenced by the Pentagon, or if China is developing another system with a more conventional warhead. The deployment of road-mobile and air-launched HGVs broadens China’s ability to hold an adversary’s targets at risk, giving missile defences another threat vector to think about in addition to China’s existing arsenal of ballistic, cruise, land-attack and anti-ship missiles.

The Pentagon has also claimed that China carried out several tests of rail guns on land. These use electromagnetic forces to launch high-velocity projectiles using a sliding armature that is accelerated along a pair of conductive rails. While the projectiles do not contain explosives like one we would find on hypersonic missiles, the projectile’s extremely high speed inflicts significant damage.

It is also believed a PLA Navy amphibious ship, photographed on several occasions mounting a large turret and gun barrel on its bow, is the test bed of a naval rail gun. The ship made several voyages believed to be for tests, although this could not be independently verified and its development status is unclear.

China has also made efforts in developing DEWs, with state media and manufacturers releasing images and videos of hand-held and vehicle-mounted laser systems. These include a hand-held destructive laser weapon offered for domestic law enforcement — ostensibly crowd control — although its designers say when set to maximum power, the laser can instantly scar human skin and tissue. It can also reportedly ignite clothing, knock a small drone out of the sky or blow up a fuel tank.

One Chinese academic has claimed the PLA used microwave weapons to incapacitate Indian troops during last year’s standoff over part of the two countries’ disputed border, although these claims have not been independently verified.

Supersonic Speed-Based Flights

Supersonic flight is one of the four speeds of flight. Objects moving at supersonic speeds are going faster than the speed of sound. The speed of sound is about 768 miles per hour at sea level, which is about four times faster than a race car. Supersonic includes speeds up to five times faster than the speed of sound. At this speed, the entire aircraft experiences supersonic airflow and travels at a speed faster than Mach 1. Generally, supersonic speeds range from Mach 1.2 to Mach 5. Boom’s Overture will fly comfortably in the supersonic regime at Mach 1.7.

Hypersonic Speed-Based Weapons and Aircraft

Hypersonic weapons are weapons travelling at hypersonic speed -between 5 and 25 times the speed of sound (0.213130319 miles per second), about 1 to 5 miles per second (1.6 to 8.0 km/s).

For aircraft speeds which are much greater than the speed of sound, the aircraft is said to be hypersonic. Typical speeds for hypersonic aircraft are greater than 3000 mph and Mach number M greater than five, M > 5.

DEW Speed

One of the greatest attributes of DEWs is that they operate at the speed of light (186,000 miles per second). So, for a hypersonic weapon that is travelling at 25 times the speed of sound, a high-energy laser can engage it at roughly 35,000 times its speed.

Airborne High Energy Laser System

The Airborne High Energy Laser (AHEL) is a DEW system designed to be mounted on airborne vehicles for neutralising ground emplacements, vehicles, or other airborne targets, and brings us closer to the ‘Star Wars’ laser systems depicted in those 80s movies.

The AC-130J Ghostrider is a medium-sized, multi-engine tactical aircraft with a variety of sensors and weapons for air-to-ground attack to replace the AC-130U/W aircraft. The Joint Task Force or Combatant Commander will employ units equipped with the AC-130J to provide close air support and air interdiction using the battlespace wide-area surveillance, target geolocation, and precision munition employment. Additionally, the AC-130J provides time-sensitive targeting, communications, and command and control capabilities.

The Air Force refers to the AHEL’s ability to damage targets as ‘scalable effects,’ meaning the beam could be used for melting a vehicle’s tyres or disabling communications antennae without any sort of explosion. In other circumstances, the AHEL could be used to start fires within enemy positions, potentially detonating stored munitions or disabling important equipment. With a standoff range on the order of 10 km, firing an invisible beam of light, such attacks would be clandestine and deniable.

The US Special Operations Command (USSOCOM) AHEL system on the AC-130J progressed towards flight demonstration in late FY22. The USSOCOM began a critical design review of the AHEL system in August 2020. USSOCOM identified an unfunded requirement to accelerate the exploration of tactics, techniques and procedures, and the concept of employment of an AHEL on an AC-130 aircraft. The experimentation proposed by SOCOM included defence research laboratories and industry working to advance directed energy systems for integration on various types of military aircraft.

Thus, all the attributes of DEWs make a wide range of subjects, ranging from human beings to Supersonic Fighter Aircraft susceptible to being partially damaged to being completely destroyed.

Lasers usually fall under 1mm to 750nm wavelength known as Infrared and 750nm to 400nm wavelength known as visible light. Microwaves use mm to cm of wavelength which is about 1000 times longer compared to laser waves.

Difference between Laser Weapon and Microwave Weapon systems

The following table mentions major differences between laser weapon and microwave weapon-based systems.

The author is a National Safety, Security, Aviation and Avionics Analyst. Views expressed are personal.

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