Electromagnetic pulse: just about the complex
In the global network, you can now find a hugethe amount of information about what an electromagnetic impulse is. Many are afraid of him, sometimes not fully understanding what is at stake. Oils in the fire poured into scientific television broadcasts and articles in the yellow press. Is not it time to understand this issue?
So, the electromagnetic impulse (EMR) isperturbation of the electromagnetic field, which affects any material object located in its zone of action. It affects not only current-carrying objects, but also dielectrics, only a little in another form. Usually the concept of "electromagnetic pulse" is adjacent to the term "nuclear weapons". Why? The answer is simple: it is during a nuclear explosion that EMR reaches its greatest value from all possible. Probably, in some experimental installations it is also possible to create powerful perturbations of the field, but they are of a local nature, but in a nuclear explosion large areas are affected.
By its appearance, the electromagnetic pulse is obligedseveral laws, which every electrician encounters 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 a current flows, then a field is always registered 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 consequence, a current. It is usually specified that the conductor forms a chain, although this is only partly true, since eddy currents create their own contours in the volume of the conducting substance. A nuclear explosion creates an electron motion, hence a field arises. Further everything is simple: lines of tension, in turn, create induced currents in surrounding conductors.
The mechanism of this phenomenon is as follows: due to the instantaneous release of energy, elementary particle flows (gamma, alpha, X-rays, etc.) occur. During their passage through the air molecules "knock out" electrons, which are oriented along the magnetic lines of the Earth. A directional motion (current) is generated that generates an electromagnetic field. And since these processes proceed with lightning speed, one can speak of an impulse. Further, in all the conductors in the field of action (hundreds of kilometers), a current is induced, and since the field strength is enormous, the current is also large. This triggers the activation of the protection systems, the fuse blown-up to the point of ignition and irreparable damage. The action of EMP is subject to all: from integrated circuits to power lines, however, to varying degrees.
Protection from EMR is to prevent the inducing action of the field. This can be achieved in several ways:
- move away from the epicenter, as the field weakens with increasing distance;
- screen (with grounding) electronic equipment;
- "dismantle" the circuit, providing gaps in view of the large current.
Often one can meet the question of how to createelectromagnetic pulse with your own hands. In fact, every person faces it daily by clicking the light bulb switch. At the moment of commutation, the current briefly exceeds the rated current tens of times, an electromagnetic field is generated around the wires, which induces an electromotive force in the surrounding conductors. The strength of this phenomenon is simply not enough to cause damage comparable to the EMP of a nuclear explosion. Its more pronounced manifestation 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 a large effective value.
