The global network now you can find a wealth of information about what is an electromagnetic pulse.Many are afraid of him, sometimes not fully aware of what is at stake.Fuel to the fire pour science television programs and articles in the tabloid press.Is it time to look into this issue?
So, electromagnetic pulse (EMP) - the disturbance of the electromagnetic field that affects any material object in its area of action.It affects not only the conductive object, but also on the dielectrics, but in a slightly different form.Usually, the term "electromagnetic pulse" is adjacent to the term "nuclear weapons."Why is that?The answer is simple: it is a nuclear explosion EMR reaches its greatest value of all.Probably, in some experimental facilities also manages to create strong perturbations of the field, but they are local in nature, and that's a nuclear explosion affected large areas.
His appearance electromagnetic pulse indebted to several laws, which is faced on a daily basis every electrician.As you know, the directional movement of elementary particles having an electric charge, is inextricably linked with the magnetic field.If there is a conductor through which current flows around the field is always recorded.Conversely, the impact of the electromagnetic field in the conductive material generates an EMF in it and, as a consequence, current.Usually specify that the conductor forms a circuit, although this is only true in part because the eddy currents produce their own contours within the scope of the conductive material.Nuclear explosion creates a movement of electrons, therefore, there is a field.Then everything is simple: line tension, in turn, create induced currents in the surrounding conductors.
The mechanism of this phenomenon is as follows: due to the instantaneous release of energy flows arise elementary particles (gamma, alpha, X-rays and so on.).During their passage through the air molecules "knocked out" electrons, which are guided along the magnetic lines of the Earth.There is a direction of movement (current) generates an electromagnetic field.And as these processes occur with lightning speed, we can talk about momentum.Further, in all the conductors located in the area of the field (hundreds of kilometers) induced current, as well as the field strength is enormous, the current value is also large.This triggers the security system fuse blowouts - until the fire or permanent damage.EMI is subject to the action of everything from integrated circuits to the power lines, albeit in varying degrees.
EMI shield is to prevent inducing of the field.This can be achieved in several ways:
- away from the epicenter, as the field weakens with increasing distance;
- screening (grounding) electrical equipment;
- «dismantle» the scheme by providing gaps in view of a large current.
You can often find the question of how to create an electromagnetic pulse with their own hands.In fact, every person is faced with it every day, flipping a switch light bulbs.At the time of switching current is temporarily exceed the nominal ten times around the wire generates an electromagnetic field which induces in the surrounding conductors, an electromotive force.Just the power of this phenomenon is not sufficient to cause damage comparable to the EMP of a nuclear explosion.More pronounced its display can be obtained by measuring the level of the field near the arc welding.In any case, the problem is simple: you must arrange the possibility of occurrence of an instantaneous large electric current effective value.
