How can an electromagnetic pulse destroy electronic devices?

Answer 1

One word:induction. When an electromagnetic pulse (EMP) hits, a big magnetic field "sweeps" everything in its path. The moving magnetic field (because it travels out from where it was created) will induce electromotive force (EMF) or voltage, if you prefer, in all kinds of stuff. There are tiny traces on circuit boards, and there are component leads and all kinds of conductors that are acting like little antennas inside electronic equipment. And these little antennae will "receive" the magnetic "signal" from the pulse and convert some of its energy into voltage. Because the pulse is so large, the voltage will be high, and will be high enough to damage components and circuits in all kinds of equipment. This will knock electronic devices out of commission. Permanently. Shielding is possible, but we can only do a limited amount of that. It's a whole are of investigation, and a lot of it is "top hush" because the applications for the shielding are mostly military. Looked at another way, if an EMP hits because someone set off a nuclear weapon, I'd rather that military aircraft fly and my computer go down than the other way 'round. Certainly the military would, too, and their budget pays for the work.

Answer 2

no an EMP only hurts electrical devices. one could theoretically temporarily disrupt our nerves, but that would only be temporary, and would require an EMP on a much more massive scale than every seen before... i.e. created from multiple nuclear weapons. however if that occurred, i'd be more concerned with the radiation than the EMP.

Answer 3

People require no protection directly from EMP unless they have implanted electronic medical devices, or if they are hooked up to electrically powered life-support. Equipment can be protected against EMPs through the construction of a Faraday Cage.

A Faraday Cage is essentially an enclosure made of suitable conductive material(s) that allow the pulse to be excluded from the interior of the chamber.

Good examples of everyday Faraday Cages would include an aeroplane in flight, and a microwave oven. In the case of an aeroplane in flight, a lightening strike (an EMF pulse) is conducted around the plane to ground. In the case of a microwave oven, the Faraday Cage prevents the microwaves from leaking out.

You can build a Faraday cage or room in your basement, but materials are problematic. From recent research, the experts disagree about what would be the best over all material. Most do agree that pure iron would be best, but not many consumers can access sources of pure iron sheets, and such might be a bit over kill. There are suggestions that metalized bubble wrap or mylar sheeting might be sufficient if layered, but there seems to be no information on the internet suggesting how many layers would be effective. Others suggest screens of different metals, and expanded copper or brass sheets brazed together to form a cage that would rest atop a non-conductive base (discussed below) will work. One source recommended a simple metal shed, or sheets of galvanized steel, and the Faraday rooms I saw on line used by industry were constructed of galvanized steel.

What is important is grounding the cage. For a Faraday cage or room to be effective at all it must be grounded. This can be accomplished by driving a copper rod into the soil. The wise person would wonder how deep it should be driven. Most will tell you three feet is sufficient, but with an EMP we are talking about huge energy levels, that must be diffused very quickly. The deeper the better. Standard military grounding for nuclear weapons is nine feet (three 3-foot sections of copper grounding rod driven into the soil).

Now to the base. Wood will work, however keep in mind that dry wood is non-conductive, and wet wood can be quite conductive. Either a vapor barrier must be placed between the base and any water or moister source, or a different base material must be chosen. Concrete, depending on its constituents, can also be conductive to some degree, so avoid using it. Think ceramic floor tile. The cheapest I found on line was for $1.55 a square foot. A ten by ten foot room would cost $155.00 to floor.

Of course, you can build smaller individual Faraday cages for each item you want to protect. A small tin box lined with cardboard or a galvanized metal trashcan resting atop a plastic base (perhaps a galvanized can inside a plastic can) will do well to shield an emergency radio and other items, just remember to ground it (and if grounding something in a basement, the easiest way to do this is to attach a simple grounding braid to the central water line or drain line).