In the global network, you can now find a huge amount of information about what an electromagnetic pulse is. Many are afraid of him, sometimes not fully understanding what is at stake. Scientific television programs and articles in the yellow press add fuel to the fire . Is it time to sort this out?
So, an electromagnetic pulse (EMP) is a perturbation of an electromagnetic field that affects any material object in its area of effect. It acts not only on current-conducting objects, but also on dielectrics, only in a slightly different form. Usually the concept of "electromagnetic pulse" is adjacent to the term "nuclear weapons". Why? The answer is simple: it is in a nuclear explosion that EMR reaches its greatest value of all possible. It is likely that in some experimental facilities it is also possible to create powerful field perturbations, but they are local in nature, but large areas are affected by a nuclear explosion.
The appearance of an electromagnetic pulse is due to several laws that every electrician is faced with in everyday work. As is known, the directed motion of elementary particles, which has an electric charge, is inextricably linked with the magnetic field. If there is a conductor through which current flows, then a field is always recorded around it. The converse is also true: the effect of an electromagnetic field on a conductive material generates an emf in it and, as a result, a current. It is usually specified that the conductor forms a circuit, although this is only partially true, since eddy currents create their own circuits in the volume of the conducting substance. A nuclear explosion creates the movement of electrons, therefore, a field arises. Further, everything is simple: tension lines, in turn, create induced currents in the surrounding conductors.
The mechanism of this phenomenon is as follows: due to the instant release of energy, flows of elementary particles arise (gamma, alpha, x-ray radiation , etc.). During their passage through the air, electrons “knock out” from the molecules, which are oriented along the Earth’s magnetic lines. There is a directional movement (current), generating an electromagnetic field. And since these processes proceed lightning fast, we can talk about momentum. Further, in all conductors located in the field of action of the field (hundreds of kilometers), a current is induced, and since the field strength is huge, the current value is also large. This causes the protection systems to trip, the fuses to blow - even to the point of fire and permanent damage. Everything is subject to the action of EMR: from integrated circuits to power lines, however, to varying degrees.
Protection against EMR is to prevent the inducing action of the field. This can be achieved in several ways:
- move away from the epicenter, since the field weakens with increasing distance;
- to shield (with grounding) electronic equipment;
- “disassemble” the circuit, providing for gaps taking into account the large current.
You can often come across the question of how to create an electromagnetic pulse with your own hands. In fact, each person encounters him daily by flicking a light bulb switch. At the time of switching, the current briefly exceeds the nominal by tens of times, an electromagnetic field is generated around the wires, which induces an electromotive force in the surrounding conductors. It’s just that the strength of this phenomenon is not enough to cause damage comparable to the electromagnetic radiation of a nuclear explosion. A more pronounced manifestation of it can be obtained by measuring the level of the field near the arc of electric welding. In any case, the task is simple: it is necessary to organize the possibility of the instantaneous occurrence of an electric current of large effective value.