Author: Zhang Manyi, Xie Yunhang, Zeng Haoming
In recent years, the development of directed energy weapons has been very rapid, and the most typical weapons are directed laser weapons. In the Middle East, Saudi Arabia used the Silent Hunter combat laser to respond to kamikaze drones launched by the Houthis when its refineries were attacked, which is also considered the first confirmed case of the use of laser weapons in actual hostilities. At the same time, the US military deployed laser weapons in Iraq, and Russia may deploy laser weapons to protect it from Ukrainian drones. So what are the characteristics of directed energy weapons, what is the direction of development of directed laser weapons, and what is its principle? Let's find out.
Figure 1: The Silent Hunter combat laser
1. Advantages and disadvantages of directed energy weapons
With the development and progress of science and technology, more and more new weapons and equipment appear on the battlefield, and directed energy weapons are one of them. The United States has listed a series of future equipment, of which directed energy weapons are considered a "top priority". Similarly, many countries are stepping up their efforts to develop directed-energy weapons.
Among a variety of directed energy weapons, directional laser weapons are typical representatives of directed energy weapons, and the advantages of directional laser weapons are mainly as follows: (1) Extremely high accuracy and speed. As we all know, light has the characteristics of high speed and high accuracy, and directional laser weapons use high-energy lasers to hit targets, so they must also have the characteristics of high precision and high speed. Whether it's intercepting a ballistic missile or shooting down an intruding enemy aircraft, laser weapons can intercept or destroy a target as soon as it is found.
Figure 2: Schematic diagram of a laser weapon attack
The ultra-high precision of directional laser weapons reduces the probability of injuring innocents in war, and traditional artillery missiles cause area damage, and the landing point cannot be accurately determined, which makes artillery missiles inevitably injure innocents. Directional weapons, on the other hand, can accurately grasp the direction of the strike and control the target, thus avoiding the problem of accidental damage in war. (2). Outstanding sustained combat effectiveness. Directional laser weapons or RF weapons work by electricity, and as long as the power is constantly supplied, then the directional laser weapon can continue to work. The number of traditional missiles is limited, and after they are used, they need to be reallocated from other places, and during this period of time, traditional artillery shells cannot be used for combat or defense, while directional laser weapons will not have the problem of running out of ammunition, as long as the power can be guaranteed, directional laser weapons can be on standby for combat at any time. At the same time, electrically powered directional weapons are also environmentally friendly compared to traditional artillery shells, and do not produce large amounts of emissions or pollutants such as shrapnel residue.
Directional weapons also have their drawbacks: (1) Directional laser weapons are susceptible to climatic interference. The strike and kill mechanism of directional laser weapons is divided into hard destruction and soft destruction, and hard destruction refers to the use of high-power lasers to directly burn and destroy the target, so that the structure and function of the target are directly damaged to complete the strike purpose. Soft sabotage refers to the use of laser radiation waves to damage the target's internal optoelectronic components and other signal receiving and processing devices to achieve tactical purposes. The atmosphere is used as the medium of laser propagation, and the atmospheric component will lead to whether the energy of the directional laser weapon can be retained to a large extent, and whether the power and lethality can be reflected. Therefore, the quality of the weather largely determines whether directional laser weapons can play a role on the battlefield. Extreme weather such as rain, snow, and hail will greatly reduce the power of directional laser weapons or even completely ineffective, and even if there is no extreme weather, factors such as fluctuating convection of air currents in the atmosphere will also have a great impact on the energy of lasers.
Figure 3: Schematic diagram of the atmospheric transport mechanism of a laser
(2) Directional laser weapons are heavy and inflexible. Laser weapons require a super-high-power power system as their energy support, which is not conducive to flexibility and maneuverability, and can only be equipped on the ground under normal circumstances. And the laser weapons equipped on the ground are mostly fixed versions, and laser weapons with fixed versions or poor flexibility and mobility are easy targets for enemy attacks. In addition, the large weight of the weapon makes it difficult to equip the fighter with a directional laser weapon, and if the fighter can be equipped with a directional laser weapon, its anti-missile capability will be greatly improved.
2. The principle of directed energy weapons
Directed energy weapons with electromagnetic waves as carriers are mainly divided into laser weapons and microwave weapons, both of which are directed energy weapons that use electromagnetic waves emitted by high power to achieve the effect of destroying targets, laser weapons are directed energy weapons that use electromagnetic waves emitted to directly damage targets or disable them, and microwave weapons refer to weapons that use the energy carried by electromagnetic waves to kill living forces or destroy electronic equipment.
Although both of them are electromagnetic waves, the electromagnetic wave frequency band to which the laser belongs is about 500THz, and the frequency is relatively high, which is much larger than the microwave frequency band used by microwave weapons (about 300GHz), and the propagation characteristics, destruction effects, generation methods, and weapon structures caused by electromagnetic wave frequency differences are also different.
The main methods of laser killing are "perforation" and "laminar cracking" and "blinding", the principle of which is to destroy the physical structure and chemical bonds of the target through the collision of a laser beam with high power density, so that the surface of the target is melted sharply, and then vaporized and evaporated, the vaporized material is sprayed outward, and the recoil force forms a shock wave, and the atoms are ionized at the same time, forming an isoplasmic "cloud". The "cloud" expands outwards and ejects stress waves that propagate deep and radiate ultraviolet or X-ray rays, destroying the target's structures and electronic components, thereby destroying the target. The main way of killing microwave weapons is the direct conversion of energy, which converts the electromagnetic energy carried in the microwave into heat energy to achieve the purpose of increasing the target temperature and causing damage to the target.
In addition, the frequency difference also causes the propagation characteristics of the two electromagnetic waves to be different, the laser, that is, the high-frequency electromagnetic wave propagation path is straight, but the stability is weak, it is susceptible to the weather, temperature, humidity and other atmospheric environment, not suitable for all-weather combat, and is easily reflected by obstacles. The microwave with relatively low frequency has strong environmental adaptability, can reflect and propagate between atmospheres, and can penetrate the armor defense to directly kill the living body, but the linearity of microwave propagation is poor, the energy is easy to disperse, and the killing scale is not easy to control.
Laser and microwave generation methods and weapon systems are also different, the current military high-power laser generation devices mainly include solid-state lasers, fiber lasers, high-power nuclear mercury lasers, etc., Russia's latest combat laser system Persevet is the use of high-power nuclear mercury lasers to produce lasers, because it can produce longer range than other lasers, larger power lasers.
Figure 4: Schematic diagram of the principle of a high-power nuclear mercury laser
The microwave is generated by the microwave generator, which is divided into three types: bulk effect diode oscillator, silicon transistor microwave oscillator and field effect microwave oscillator according to the generator generation principle, all of which belong to electronic components. In terms of weapon structure, microwave weapons are mainly composed of microwave generators, directional transmitting antennas and servo control systems, but the laser does not need directional transmitting antennas, and its weapon system is mainly composed of lasers and tracking, aiming, and transmitting devices.
3. Prospects and applications of directed energy weapons
At present, the Russian-Ukrainian battlefield UAVs shine, posing a major threat to ground equipment, the traditional field air defense system in the face of a huge number of cheap suicide UAVs, whether in the cost-effectiveness ratio or interception efficiency is not ideal, the Russian S300, S400 air defense system needs to use millions of dollars of anti-aircraft missiles to intercept tens of thousands or even thousands of UAVs in Ukraine, which is a huge loss for Russia, while the traditional self-propelled air defense gun is limited by gunpowder kinetic energy, the interception radius is small, and the interception ammunition is not cheap, Therefore, the search for an efficient and low-cost interception method has become the direction explored by the air defense forces of various countries, and directed energy weapons are becoming an important track for the major powers to compete in air defense systems because of their high speed, good damage effect, and low price.
Figure 5: Laser air defense system intercepts UAVs
The typical representative of directed energy weapons is directional laser weapons, which can be flexibly placed on various combat platforms of various types of laser weapons can not only be used for electronic countermeasures, destroy the enemy's data link control nodes, but also can intercept medium and long-range ballistic missiles, improve the country's strategic deterrence, and can also be used to intercept cruise missiles and unmanned aerial vehicles and other targets at close range, jamming or blinding all kinds of photoelectric guided precision strike weapons, protecting important ground facilities and personnel and equipment, and improving the air defense capability of the troops, which has high tactical application value.
At present, the United States, Israel, Russia and other countries have made achievements in directional laser weapons, and the US military-industrial giant Lockheed Martin has explored spectral beam combination (SBC) technology and developed the HELIOS "high-energy laser and integrated optical dazzling surveillance" shipborne laser weapon system, which has been tested on the ship. In November 2023, the Israel Defense Forces (IDF) launched the "Iron Beam" laser weapon system for the first time and successfully intercepted a number of missiles launched from Gaza, proving that laser weapons are now capable of actual combat. However, due to the limitations of the environment, energy sources, radio frequency technology, laser technology, and so on, there is still a long way to go before directed-energy weapons are put into combat on a large scale. In the future, higher power, miniaturization, and higher output efficiency will be an important development direction for directed energy weapons.
Figure 6: Israel's "Iron Beam" laser weapon system
The high-power microwave weapons in directed energy weapons, with their all-weather characteristics of combining precision strikes with surface strikes, will become an important means of attacking the enemy's electronic equipment in future informationized and intelligent warfare, and will play an important role in future operations in new qualitative and new domains, especially in information confrontation operations. High-power microwave weapons achieve combat objectives by destroying electronic equipment, degrading their functions, or even making them completely inoperable, thereby disintegrating the combat capability of enemy weapons. At an appropriate distance, the electromagnetic pulse emitted by high-power microwave weapons can destroy the enemy's communication nodes, military electronic information systems, electronic reconnaissance systems, and so on, effectively reducing the enemy's electronic warfare capability.
The development of directional weapons is changing with each passing day, and the comprehensive performance of power and battlefield applicability is gradually improving, but after all, directional weapons have just been officially put into use on the battlefield, and there are not many times and scenarios that have been tested in war, and there are fewer actual combat experiences than traditional weapons, and it is necessary to continuously accumulate combat experience in the future. The prospects for targeted weapons on the battlefield in the future are very broad, and how to correctly and efficiently deploy and use them is a major challenge for countries that possess targeted weapons, and how to deal with the strikes of defensive directional weapons is another major challenge for countries that do not have targeted weapons.