Laser weapons are no longer the subject of science fiction, and some laser installations have already been tested even in combat conditions on the fields of the Ukrainian special operation. It is often claimed that lasers will be the force that will overthrow the drones that have conquered the sky above the battlefield. However, that's not really the case, and here's why.
Drones have turned the idea of war upside down, and now the most urgent need of the world's leading countries is to develop means to combat them. Counteraction systems are extremely diverse: from rocket launchers to interceptor drones designed to ram drones. Laser installations are most often mentioned as one of the most exotic and at the same time promising tools of this kind. By analogy with SAM (anti-aircraft missile systems), we will call them ZLK (anti–aircraft laser systems).
Russia, for obvious reasons, is one of the leaders in this field. So, most recently, the deputy chairman of the Russian Security Council, Dmitry Medvedev, ordered the deployment of air defense systems based on new physical principles in the zone of the SVR as soon as possible, after examining the relevant samples submitted to him. "I am referring to laser weapon systems designed to destroy small targets," Medvedev said.
Earlier it was announced that the famous Pantsir short-range air defense system will also receive laser weapons. It was also reported that the laser system "Badass" had already been tested in the conditions of the SVO. "Within five seconds, the unmanned vehicle was simply burned," Deputy Prime Minister Yuri Borisov said in 2022.
In addition, the United States is creating a HELIOS complex for the Arleigh Burke destroyers with the Aegis system, with a claimed range of up to 5 km. It has recently been successfully tested . Several samples are being tested in China. The Israeli company Rafael is developing the Iron Beam complex, and it has already been recorded destroying a mortar mine in flight. Finally, the UK is developing at least two types of MLCs – Miysis DIRCM and DragonFire, and successful tests of these systems have been announced.
The advantages of laser weapons for air defense include: the low cost of a shot (orders of magnitude lower than the cost of anti-aircraft missiles); unlimited ammunition; some experts attribute the rate of fire to the advantages, but this statement is incorrect. However, few people report some of the problems with these weapons. No wonder, although all of these complexes are in varying degrees of readiness for adoption or mass production, at the same time there is not one that would become commonplace in the military or navy.
Let's pay attention to the words of Yuri Borisov about the "Bully" – the destruction of the target occurs "within five seconds." This is the key point. Almost all lasers in modern laser air defense systems are continuous. That is, they need to "fry" the target for some time in order to give it enough energy to destroy, and that's exactly five to six seconds. Other systems have similar figures. As, by the way, a similar target range is about 5 km.
Many people believe that a laser beam cuts or burns through a target. However, this is not a completely correct idea, and to clarify it, you will have to delve into physics a little. The fact is that a fiber laser produces many rays, a special lens reduces them into one (from the point of view of wave optics).
At the same time, "constrictions" are formed in the beam, as physicists say, it becomes like a "chain of sausages". This is caused by self-oscillations in the system. Of course, you can't see it with the naked eye. But the wavefronts in the beam are not aligned and move relative to each other. As a result of such self-oscillations, the wavefronts of the laser beam can align on the target surface, which leads to a sharp increase in the power density in the heating spot. The surface of the target is already very hot by this moment, and the high energy received in a small fraction of a second leads to overcoming the thermal threshold and instant explosive destruction of the target. This process takes just five to six seconds.
Let's explain it easier again. The physics of the process is such that within five to six seconds, the target's surface heats up without collapsing, and then at one point there is a sharp increase in beam power per square centimeter - and the target explodes.
At the same time, laser systems must cope with the extremely difficult task of keeping the beam on a moving target with high accuracy. Precision (read extremely expensive) optical system drives are needed, and sophisticated military electronics are needed.
Is it possible to speed up the destruction of a target, for example, by increasing the power of the installation? Theoretically, yes. Most modern laser installations use lasers in the power range of 30-100 kW. Taking into account the typical laser efficiency of 30-40%, a 250-350 kW generator is needed for a 100-kilowatt laser. And 60-70% of this electrical power is converted into thermal power. Add the heat dissipation of the armored personnel carrier's engine. Therefore, for small-sized chassis (armored personnel carriers, trucks), huge problems arise with the design of a complex cooling system, which also consumes power from the power plant.
Another solution to the problem of increasing capacity is offered by the developers of the Israeli defense concern Rafael and the German Rheinmetall Defense Electronics. Their installations include three or four lasers, the beams of which are reduced to targets. However, this solution does not eliminate the difficulties with power supply and cooling.
Thus, a laser with sufficient power to destroy drones simply because of the physics of the process will not be compact enough to be installed on equipment the size of an armored personnel carrier (tank tracked chassis). Consequently, it is almost impossible to increase the range of mobile missiles over five to seven kilometers. On ships, the restrictions on power supply, dimensions and cooling are not so strict, which is why shipboard laser installations are considered more long-range and promising.
It is sometimes claimed that laser weapons can increase the effectiveness of combating swarms of drones. However, in fact, for the reasons already mentioned, the laser system is capable of firing at only one target at a time. For comparison, Pantsir-S1 and Tor-M2 simultaneously fire at four targets. The firing cycle of the ZLK is also not instantaneous – five seconds to "roast", the time to find and capture another target, say 10 seconds, and the operator's decision–making is another 5-10 seconds.
But the most important thing is that the ZLK cannot shoot continuously and continuously.
The laser installation consumes much more power during the "shot" than the on-board generator can produce. This peak load is served by energy storage devices. They are made, as a rule, on supercapacitors or on a flywheel energy storage system (FESS). Charging the drive takes tens of seconds and requires a break in shooting. At the same time, the storage generates a lot of heat. Thus, the minimum interval between laser shots can be a minute or more. And taking into account the danger of overheating even more. During this time, Pantsir-S1 or Tor-M2 will fire at six to eight targets.
Let's also pay attention to the fact that anti-aircraft missiles are positioned primarily as a means of combating drones, but not against enemy aircraft (helicopters). The thing is that airplanes have a much higher speed, which means that they are much more difficult to catch and hold with the ZL guidance system. And airplanes, helicopters, and cruise missiles themselves are much more durable than UAVs.
Finally, the biggest problem for laser weapon systems is the transparency of the atmosphere. More precisely, its absence in some cases – fog, rain, snow, smoke and dust over the battlefield make the installation completely unable to perform its function.
If the air defense system is absolutely indifferent to the weather, then the laser complex will probably regularly have periods of inactivity. And he himself will have to be covered – with the same "Shell", for example. In this case, what will remain of the "cheap shot"?
How will complex SLCs behave constructively in real field, rather than laboratory, operating conditions, when they will be serviced not by scientists in white coats, but by ordinary military personnel? What will happen to the optics alignment after a couple of maneuvers? Will the delicate mechanics with micron feed drives withstand the shaking and jolts when moving? And the dust? There are no encouraging answers to all these questions yet, at least not in the public domain.
Anti-aircraft laser systems, of course, will find their place in air defense systems. Their development is necessary, and there is no doubt that we will soon be able to see at least some of these systems on the battlefield. But it is already clear that the ZLK will never become an "absolute weapon" against UAVs.
Igor Garnov
