For the last couple of years, the meme of an EMP attack against the United States has been an integral part of the thoughtbase of the prepper community. So the idea goes, the next major attack by a foreign power will involve not the bombing of a major city but bombardment with an electromagnetic pulse (local mirror, snapshot taken 20170310 @ 2030 hours PST8PDT). Due to the fact that "electromagnetic" is kind of a loose term, sometimes they mean an actual magnetic field, sometimes they speak of a microwave burst (which means that you've got bigger problems than your electronics getting fried - humans are mostly water, after all), sometimes they mean RF, and sometimes they mean some other unspecified thing. At any rate, the pulse emitted is enough to fry all major electronics, knock out the power grid, and generally return the country to a hunter-gatherer mode of existence for the forseeable future. Just how this happens is never really explained but the answer can be determined with basic physics. Electricity and magnetism are two sides of the same coin: Where you have one, you have the other. Pass a powerful enough magnetic field through a long enough wire and it might generate enough voltage to blow out the components soldered to it. Do that to enough electronic devices in the area, and all the equipment goes down. Seems simple enough.
So, what's actually the score here?
Fifty-five years ago, the United States government wanted to find out what would happen if somebody popped off a nuke in space. So, the initiated a project called Starfish Prime, in which they detonated a 1.4 megaton nuclear device 240 miles above the surface of the Earth, a distance which is on the low end of low earth orbit. The detonation created an artificial aurora that was seen in the sky for thousands of kilometers around, in addition to scattering fallout in LEO and the upper atmosphere. To be fair it was probably only a little fallout, relatively speaking, because it was only the remnants of the nuke itself and not the vaporized debris one would expect of a terrestrial detonation. It was observed by the project's scientists that the orbital detonation generated an electromagnetic pulse that briefly disrupted electrical power on the ground hundreds of kilometers around where the center of the blast sphere was. It was later discovered that Telstar-1, the first comsat launched into orbit, was damaged by the radiation. In Hawaii, the power surges were such that street lights blew out, knocked out telephones, and caused radio blackouts. Physicists later determined that the burst of electrons loosed by the detonation were trapped by the Earth's geomagnetic field and didn't return to a low-energy state for several months. This had the net effect of interfering with radio propagation for about as long, making communications difficult.
Seems legit so far.
However, for scientific accuracy we need to distinguish between the phenomena of the pulse itself (which, by definition, is a finite phenomenon that fades after a certain period of time), the fallout (which is dust light enough to skim around in orbit along with other sorts of space debris until it loses enough velocity to enter the atmosphere and burn up on the way down), and the electron cloud (I don't have a better name for it) trapped in the edge of the geomagnetic field. Each of these phenomena are more or less cotemporaneous (modulo the pulse) and have different manifestations, though when taken as a sum seem to represent what the prepper community is talking about. Fair enough.
I was going to write a point-by-point breakdown of this set of ideas but I discovered, during the course of my research, that somebody with more appropriate scientific expertise did a much better job than I could, so here's a link to it (local mirror, 20170311 @ 1439 hours PST8PDT). Please give it a read, it's fascinating stuff.
People throughout the prepping community all seem to have opinions on the matter and advice to give, including how to store computers, radio, and communications devices in various ways to shield them from an EMP. Some people advocate building faraday cages in their basements (a remarkably easy task, though you need a large, flat ground to make it work right) to storing stuff in aluminum cookie tins and burying them. Strangely, not many of them ever seem to mention learning how to get by without advanced technology, but I digress.
What gets to me is that it always seems that the stories revolve around a nuclear detonation above ground level - an airburst. In the few times that a nuclear weapon has been used offensively, they've always been dropped from airplanes and triggered at a specific altitude because, if you're going nuclear you want to maximize the destruction from your weapon. If you want to kill a city with one shot, kill as big an area as you can with that one shot. Strategically speaking, go big or go home. The set of people who are concerned about EMP attacks seem to treat airbursts as if this makes it a less-bad nuclear detonation, possibly by underestimating the destructive potential. Remember Hiroshima and Nagasaki? Fat Man and Little Boy were airbursts in the kiloton range, and they utterly flattened those cities.
Second, nobody's going to waste a nuke on an EMP, they're going to invest that nuke in taking out a major strategic target. Nukes are rare and expensive things, but popular media makes it seem as if they are more readily available than they really are. There is no shortage of rumors floating around that nuclear weapons have gone missing and/or have been smuggled into the United States and are currently hidden away. To be honest, I have no idea if nukes have gone missing or not. That seems like the sort of information that would have the highest levels of security classification, and if I knew for sure I certainly wouldn't be writing about it here. Because I don't know anything about the former, I certainly can't speak to the latter with any authority. However, the problem of acquiring fissile material aside, building a nuclear weapon isn't an easy task by any means. The descriptions and diagrams of nukes given in books and on the Internet are radically simplified and seem to be missing lots of key information that would be necessary to build even the simplest type of nuclear weapon. There's a reason why they're called "nuclear research programs," and that reason is that those governments are basically figuring out how to make nuclear weapons from first principles by re-doing the research from step zero due to how complex the physics of them are. This is also the reason why physicists who have the expertise to work on nuclear weapons and actual hard knowledge of how to construct them are so damned rare.
All of that said, that is why nobody is going to waste a nuke to generate an electromagnetic pulse. Too rare and too expensive when you could do so much more damage with them.
To be fair, EMP generators do exist on a small scale. The best sources I have access to (none of which are classified) claim that they were built by prime contractors to test how resistant to EMPs pieces of hardened equipment are. Governments contract the construction of hardware that is specifically resistent to radiation, RF interference, and yes, electromagnetic pulses, this isn't a secret. These generators, however, are limited by how much electrical power they can be fed, in both a direct (the size of the electric generators) and indirect (the maximum amount of power they can take before burning out) sense. However, like nuclear weapons, the engineering know-how to build such a weapon isn't a common thing. The electrical power required to generate an EMP strong enough to down a city would probably require so much power that the blackout caused just beforehand would accomplish the same task. Ultimately,the generally crappy state of information security today has demonstrated that it's far easier and more efficacious to compromise the security of power installations and crash them instead. Looking at it from a practical perspective, the skill level required for such a hack is significantly less than that to build a weaponized EMP generator and it's much easier to find people with the appropriate skillsets.
Taking the geopolitical perspective for a moment, let's not forget what a bad idea it would be to knock out a country's infrastructure. The world is tightly connected today, so much so that a disruption to the economy of one country has a ripple effect in markets elsewhere, seemingly proportional to how influential that country is globally (though I can't discount the possibility of a black swan event). Countries that have cut themselves off from the global Net in recent memory always seem to keep one private link open, so their stock markets can continue to trade. Doing otherwise is tantamount to economic suicide, and far outweighs the strategic benefits to their current regiemes. Take down the US economy for an unspecified period of time and you screw up the economies of other world powers, possibly including the attacker's. No bueno.
Oh, and that whole "red mercury" thing? It's a red pigment that was invented back when practical alchemy was more popular than it is now. If it actually worked there would be at least a couple of magickians who'd be power players on an international scale and the political landscape would look very different. But I digress again.
Do I think that this is going to change anybody's mind?
No. Humans are going to believe whatever they want to believe, regardless of evidence. It's been proven time and again that showing people evidence doesn't change their minds, it causes them to double down on their beliefs. We also again live in a time in which people who dissent from the general memeplexes of their communities are vociferously accused of being shills, disinformation agents, or spies. On top of all of that, not a few of the Internet texts and ebooks sold are ghostwritten by people just looking to make a little extra money on the side. In point of fact, some were written by a journalist for Vice Motherboard who then went on to write an expose' about this very thing. So, no, I don't think this article is going to change anybody's mind, or if it does it'll be the minds of only a small handful of people. However, not saying anything is tantamount to condoning, so I must make the attempt.