| Possible ways of creating electromagnetic means of active influence on an intruder.
UDINTSEV Dmitry Nikolaevich, Doctor of Technical Sciences, Associate Professor Possible ways of creating electromagnetic means of active influence on an intruderSource: «Special Equipment» magazine, No. 3, 2009 The article considers the problem of protecting important objects from penetration by unauthorized persons and promising ways of its solution using electromagnetic means of active influence on the intruder. Information is provided on the history and state of development of electromagnetic weapons, the advantages and disadvantages of some existing and promising means used to cover approaches to important objects, as well as possible options for using promising means are considered. The operating principles of existing experimental models of weapons, possible basic schemes of promising means operating on the basis of various methods of converting electrical energy into mechanical energy are considered. The problem of protecting important objects from penetration by unauthorized persons (intruders) has been and remains relevant. Such objects may be buildings, structures, sections of roads and other communications. The level of required impact on the intruder depends on the location of the object and the situation. In peacetime, at objects that are private property and similar objects, it is necessary to ensure the detention of the intruder without causing him significant damage. In a combat situation or in counter-terrorism and other special operations, as well as when ensuring the protection of potentially dangerous and vital objects, the impact on the intruder should be more severe, including the use of weapons (or other similar means) to kill. Depending on the importance of the object, a security zone of the corresponding size can be established along the perimeter of its fence on a section of land or water area. To detect an intruder and influence him at the boundaries located at a certain distance from the object, various means of signaling and destruction are used. The development, implementation and improvement of such means are carried out as science and technology develop. At various stages of the development of society, there have been qualitative «leaps» in the development of technology: the invention of the wheel, the internal combustion engine, the discovery of the possibility of obtaining and using electrical energy, and much more.
One of these qualitative «leaps» was the invention of the possibility of accumulating and using mechanical energy to throw weapons, which initiated the development of bows, stone throwing machines and crossbows. The development of weapons on this principle was limited, since attempts to increase the speed and range of the striking element entailed an increase in the mass and size characteristics of the weapons and the complexity of their use. The invention of gunpowder allowed a new qualitative level in the development of weapons of destruction, and for almost a millennium weapons of destruction using the energy of expansion of gunpowder gases were developed and improved. But in practice, for several decades now, there has been no radical improvement in the characteristics of such weapons, which indicates the exhaustion of development opportunities in this direction. It is obvious that a new principle must emerge that will allow us to move to the next qualitative level. At present, the possibilities of converting electrical energy into kinetic energy of striking elements on the principle of an electromagnetic mass accelerator [4] and converting electrical energy into explosive energy on the principle of an electrohydraulic shock [5] have been sufficiently studied. There are two known types of electromagnetic accelerators (electromagnetic guns): solenoid and rail, which are often called respectively the «Gauss gun» and rail gun — railgun, less commonly the name «Lorenz gun» [1,2]. The Gauss gun consists of a solenoid, inside which there is a barrel, usually made of an insulating material. A projectile (projectile) made of a ferromagnet is placed at one end of the barrel (Fig. 1). When an electric current flows in the solenoid, a magnetic field is created, which accelerates the projectile, «pulling» it inward. At the ends of the projectile, poles are formed, symmetrical to the poles of the coil, due to which, after passing the center of the solenoid, the projectile is attracted in the opposite direction, that is, it slows down. If the current is turned off in the solenoid at the moment the projectile passes through the middle of it, the magnetic field will disappear and the projectile will fly out of the other end of the barrel by inertia. For the greatest effect, the current pulse in the solenoid must be short-term and powerful. As a rule, electric capacitors with a high working voltage are used to obtain such a pulse. The parameters of the winding, projectile and capacitors must be coordinated in such a way that when firing, by the time the projectile approaches the middle of the winding, the current in the latter would have already decreased to a minimum value, that is, the charge of the capacitors would have already been completely spent. In this case, the efficiency of a single-stage Gauss gun will be maximum. In a multi-stage electromagnetic mass accelerator, several solenoids are used in series to increase the efficiency.
A railgun uses an electromagnetic force called the Lorentz force to accelerate an electrically conductive projectile, which is initially part of a circuit. Sometimes a movable armature is used to connect the rails [3,4]. The current flowing through the rails excites a magnetic field between them perpendicular to the current flowing through the projectile and the adjacent rail. As a result, there is a mutual repulsion of the rails and acceleration of the projectile (Fig. 2). Experiments with an electromagnetic accelerator based on the principle of the Gauss gun were conducted in the 20th century in Germany, the USSR, the USA and other countries. At the beginning of the century, a projectile weighing 15 g was accelerated to a speed of 75 m/s, and in the second half of the century, an element weighing about 1 g was accelerated to a speed of 4900 m/s [5]. Currently, work is underway in the United States to create a cannon based on the railgun principle (Fig. 3). In 2008, during tests, an initial velocity of 2,500 m/s and kinetic energy over 10 mJ were achieved with a projectile weight of over 3 kg. The projectile's estimated range is about 400 km, and the circular error probable from the target is up to 5 m (provided by GPS navigation equipment). For comparison, the firing range of the Mk 45 127 mm naval cannon is 24 km (13 nautical miles) [6]. It is planned to be adopted as a launcher for warships in the period 2014-2020. An electromagnetic accelerator as a weapon (launcher) has a number of advantages over weapons that use the energy of an explosion or expansion of powder gases to propel a projectile (striking elements). First of all, it is possible to change the initial velocity (respectively, the flight range and energy) of the projectile in a wider range, as well as lower recoil, load on the barrel, noise of the shot, etc. Secondly, the high flight speed of the projectile (tens of times exceeding the flight speed of projectiles of existing artillery systems) ensures that the target is hit due to high potential energy, without the use of explosives in the design of the projectile. At the same time, the use of electromagnetic accelerators as a weapon is associated with a number of problems, and the main one is the high energy intensity, which determines the scope of application of these means: warships, security systems for hydroelectric and thermal power plants and other mobile and stationary objects that have a power supply system with a sufficient power reserve.
When comparing weapons based on electromagnetic accelerators and weapons based on the energy of explosion (expansion of powder gases), it is also necessary to take into account that the presence of explosives in ammunition makes them very dangerous during production, transportation, storage and use. Taking into account all the costs associated with ensuring the safety of these processes, the effect is very significant. The results achieved in the course of theoretical and experimental studies with electromagnetic mass accelerators allow us to consider the possibility of their practical application not only for solving problems of artillery, but also engineering ammunition, where the masses and flight speeds of the thrown elements are significantly lower [ 8 ]. With the help of an electromagnetic mass accelerator, not only «monolithic» objects of various masses can be thrown, but also groups of small objects, that is, analogs of the damaging elements of fragmentation antipersonnel mines (APM), for example, mines of the MON, OZM-72 series. The throwing installation (Fig. 5) based on an electromagnetic mass accelerator (single-stage), manufactured in laboratory conditions at the Military Institute (Engineering Troops) of the Combined Arms Academy of the RF Armed Forces, in the first experiments made it possible to achieve a speed of a thrown element of 22 m/s with a mass of 210 g, which corresponds to an energy of 51 J. This energy is sufficient to injure biological objects. Work is currently underway to optimize the parameters of the installation in order to achieve better results. The disadvantages of the launcher include its higher cost and weight and size characteristics than existing engineering ammunition.
At the same time, the electromagnetic launcher has a number of important advantages over engineering ammunition (EPA) using the energy of an explosion or powder gases: a higher level of safety in operation; the possibility of multiple actions, like a magazine automatic weapon; less noise and, accordingly, stealth of action; the ability to change the parameters of destruction (flight range, weight, number of striking elements). The electromagnetic launcher can be mounted on a rotating support with an electromechanical drive, which will provide the ability to re-target the installation within a wide sector (if necessary — up to 360 °). The possibilities for the development of EPA are not limited to the use of an electromagnetic mass accelerator. An electrohydropercussion installation can also be used as a source of kinetic energy for striking elements [9]. The electrohydraulic effect (impact) consists of the occurrence of high pressure as a result of a high-voltage electric discharge between electrodes immersed in liquid. In the ammunition, an electrohydraulic impact unit is used as a source of kinetic energy for the striking elements, which includes a container filled with a working liquid. Structurally, the warhead of the ammunition can be made in various versions: a cast-iron container with external notches to ensure uniform fragmentation of the body, a vessel with ready-made striking elements (steel balls, rollers, etc.) distributed on the outside along the walls, and others. The tank is filled with a working fluid (water, transformer oil). Two electrodes are inserted inside it. In the first version, the role of one of the electrodes is played by the cast-iron body of the munition. The electrodes are connected to a high-voltage electric current pulse generator by high-voltage wires. An electrohydraulic shock is formed in the liquid by supplying pulses to the linear part, providing a spark electric discharge between the electrodes. The factors of the electrohydraulic effect ensure the destruction of the munition body and the transfer of kinetic energy to the fragments, necessary to ensure the destruction of targets within a certain destruction zone. The coil with wires is connected to the high-voltage electric current pulse generator. Figure 6 shows the structural diagram of an engineering munition based on an electrohydraulic shock. The operating principle of the anti-personnel fragmentation hydropercussion munition is similar to the engineering munition based on the electromagnetic mass accelerator (except for the warhead). When the detonation sensor (control panel) is triggered, the electric power from the source is supplied to the charger, which charges the energy storage device. The switch converts the energy accumulated in the storage device into a high-voltage pulse, which is supplied through the cable line and the connecting device to the warhead and provides a spark electric discharge between the electrodes, forming an electrohydraulic shock. The above gives grounds to believe that there is a possibility of replacing anti-personnel fragmentation mines of circular and directional destruction (including anti-personnel minefield control kits from MON-50 and OZM-72 mines) with weapons created on the basis of electro-hydropercussion ammunition or electromagnetic mass accelerator. Based on the specified means of destruction, it is possible to create an automated target destruction complex «target sensor — control unit — electromagnetic launchers» (Fig. 7). Target sensors can be installed at the approaches to the protected object in various sectors and at several lines in places where targets may appear and select targets by a number of parameters, identifying among them the objects of influence: a person with a weapon, unarmored vehicles, etc. When identifying a given target, the target sensor informs the control unit, which, taking into account the range to the target and the target parameters, gives a command to the corresponding launcher to aim at this sector, recharge the capacitors to the required capacity, activate the required number of coils, load the appropriate projectile and hit the target. Overlapping the firing sectors of neighboring launchers will increase the survivability of the system. In semi-automatic mode, the complex is prepared to hit the target and informs the operator about it («requests» permission to hit). The operator evaluates the information, makes a decision and, if necessary, gives the command to hit the target. The ability to operate the complex in this mode will reduce the time and automate the process of getting ready to hit the target and at the same time ensure selectivity of hitting. When working together in complexes and systems of means of detecting and hitting a target, a negative impact of significant pulsed electromagnetic fields created by the proposed engineering munitions on the target sensors is possible. These issues are planned to be theoretically and practically tested in the course of further research. Research into the problem under consideration is also being conducted at the Scientific and Educational Center of Vladimir State University. The result of the work carried out is currently a complex of active protection of objects based on magnetic-pulse throwing devices proposed by the university specialists [11]. The principle of high-speed magnetic-pulse throwing of solid conductive bodies has been known for a long time and is based on the occurrence of mechanical repulsive forces between conductors through which electric current flows [12,13]. The operating principle of magnetic-pulse throwing devices (MPT), capable of imparting high speeds to bodies (up to several kilometers per second), provides wide possibilities for their application in various fields of science and technology. MPT usually includes: an energy storage device, a switching device and an inductor. Capacitive or inductive storage devices can be used as energy storage devices.
Inductive storage devices are inferior to capacitive ones in terms of energy transfer efficiency, however, the energy density stored in the storage inductance significantly exceeds the energy density stored in the capacitive storage device (capacitor bank). Compact laboratory MIMUs mainly use capacitor storage devices, which are manufactured in a fairly wide range by industry. Various types of arresters are used as a switching device for MIMUs: vacuum, high or atmospheric pressure, with a solid dielectric. The following are used as inductors: single-turn solenoids, multilayer spiral solenoids, flat single-turn and multi-turn inductor coils. This article examines magnetic-pulse throwing devices, where flat spiral inductor coils are used as inductors, high-voltage pulse capacitor batteries are used as energy storage devices, and solid flat electrically conductive bodies are used as thrown bodies (indenters). The inductor is the primary circuit, with which the thrown body is inductively connected, which is the secondary circuit (Fig. 8). When the energy storage device is discharged onto the inductor coil, the current flowing through the primary circuit induces eddy electric currents in the secondary circuit, as a result of which two opposite magnetic fields are induced between the inductor and the thrown body. This leads to the emergence of intense ponderomotive forces, due to which the thrown body acquires a high initial velocity. Thus, in this process, the energy of the electric field of the capacitive storage device (capacitor bank) is converted into the energy of the magnetic field of the inductor, and then into the mechanical work of pushing the projectile out of the inductive coupling zone of the inductor, and also, partially, into heat. It should be noted that the electromagnetic means of active influence on the intruder have practically the same structure (target sensors, control system, energy storage and converters, etc.), which allows for further joint work to create a universal complex based on a unified electrical part. The proposed means will have warheads that differ in design and operating principle, allowing their differentiated use at different distances from the object while ensuring the required level of influence on the intruder. Taking into account the above, it should be noted in conclusion that the development of weapons based on electromagnetic mass accelerators is a promising direction, which is confirmed by the results of experiments conducted in the 20th and early 21st centuries. Thus, the US Department of Defense invested 36 million dollars in the development of electromagnetic weapons last year, and by the end of the first phase of the program — in 2011 — it is planned to spend another 136.7 million dollars [6]. Unfortunately, there is no similar program in the Russian Federation yet.
Literature1. Gauss K.F. Collection of articles ed. Vinogradova. — M.: AN, 1956. — P.71-96. |
