Possiblity of an electromagnetic pulse, (EMP) attack Today

[RonBush]

I recently got interested in the possibility of an electromagnetic pulse, or EMP attack after reading this article:

http://www.nytimes.com/2011/12/12/us/politics/gingrichs-electromagnetic-pulse-warning-has-skeptics.html

One thing that bothered me was this false statement in the article:

"The Missile Defense Agency, an arm of the Pentagon that maintains an arsenal of ground-based interceptors ready to fly into space and smash enemy warheads, says that defeating such an attack would be as straightforward as any other defense of the continental United States."

There have been a few successful tests, but there is definitly no "arsenal of ground-based interceptors ready to fly into space and smash enemy warheads" that could knock out an ICBM.

It would only take 2-3 atomic bombs, exploded in the right places above the USA to knock out all the electric power in the country.  For technical details read this article in wikipedia

http://en.wikipedia.org/wiki/Electromagnetic_pulse

In the near future this is something that might be done by Iran or North Korea.  It could be done by China or the USSR today.

If you knock out all the electricity in the USA, it is questionable how we would ever get it back on.  Maybe it would take years.  In that time, many millions would die.

If you want to read a worst case disaster novel about this possibility, take a look at "One Second After" by William Forstchen.  It is mostly a pretty poorly written adventure story, but the idea of
what could happen to the country if you knock out all the electricity for a year seems believable.  I got the book out of the library.  If you get bored with the writting, just read page 62-71
and 336-350 and it will sum up his idea of how bad this could be.

So what do you know about this.  Is it as possible as it seems?

[DumbAss Tanker]

To do it with 'Two or three' warheads would require extremely powerful warheads, on the order of the most powerful fusion weapons ever produced as deployable weapons, and detonation at an altitude that is subspace but still so high that it would be technically demanding for all but the cream of the most advanced countries of the world to produce.  It is not the kind of attack that could be conducted with modified or improved battlefield missiles like SCUDs.

It would take down the grid for quite awhile, of course it is the nature of those long lines that the energy concentrates most where failure starts, so it is not at all like every copper wire would be slagged down, just that there would be lots and lots of breaks.  Substations and powerplants might not be as vulnerable as many suppose, it depends on their ability to isolate or shunt such a huge surge to ground, of course the surge is coming in on the long lines where it is generated, so as soon as they start breaking, the current influx stops.

The grid is really the least of the problems, the real damage is from induced current in low-voltage digital devices where rather small induced currents will destroy them if they are unshielded (And pretty much only military and some industrial equipment is shielded).  In the past 20 years, digital controls have been added as 'Features' to all sorts of things for which they are not fundamentally unnecessary, from coffeepots on up, and most of that will become scrap metal in a major EMP event.   

[RonBush]

To do it with 'Two or three' warheads would require extremely powerful warheads, on the order of the most powerful fusion weapons ever produced as deployable weapons, and detonation at an altitude that is subspace but still so high that it would be technically demanding for all but the cream of the most advanced countries of the world to produce.

Are you sure about that?  I am no expert and you may know more about this.  However, wikipedia has a map showing that you would knock out half the country from an altitude of 120 miles, and the max altitude of a scud missile is 124 miles.
http://en.wikipedia.org/wiki/Electromagnetic_pulse#Weapon_altitude
http://www.airliners.net/aviation-forums/military/read.main/12565/

This is from the same article in wikipedia
"During nuclear tests in 1962, EMP disruptions were suffered aboard KC-135 photographic aircraft flying 300 km (190 mi) from the 410 kt (1,700 TJ) Bluegill Triple Prime and 410 kt (1,700 TJ) Kingfish detonations (48 and 95 km (30 and 59 mi) burst altitude, respectively)[27] but the vital aircraft electronics were far less sophisticated than today and the aircraft were able to land safely."

[NHSparky]

IOW, you'd have to bring one of those weapons INTO the continential US.  Now I grant you, DHS is pretty ****ing inept, but even THEY would notice something like that.

And DAT is right--the size of the blast would have to be on the order of tens of megatons.  Few if any existing nuclear weapons have that kind of capability.  Most are on the order of 500kT or less, and the ones that the Pakis, Norks, and Iranians want to play with are on the order of 5-10 kT.

[DumbAss Tanker]

It might be more than just a tad difficult to position and launch a SCUD from a point half its maximum-ordinate-producing operational range away from the desired burst location in order to achieve that.

(ETA - Disregarding for now the question of whether a SCUD would actually be able to loft a warhead of the size/weight required to that max ord at all)

[RonBush]

And DAT is right--the size of the blast would have to be on the order of tens of megatons

Not according to this:

"During nuclear tests in 1962, EMP disruptions were suffered aboard KC-135 photographic aircraft flying 300 km (190 mi) from the 410 kt (1,700 TJ) Bluegill Triple Prime and 410 kt (1,700 TJ) Kingfish detonations (48 and 95 km (30 and 59 mi) burst altitude, respectively)[27] but the vital aircraft electronics were far less sophisticated than today and the aircraft were able to land safely."

It might be more than just a tad difficult to position and launch a SCUD from a point half its maximum-ordinate-producing operational range away from the desired burst location in order to achieve that

I don't know enough to comment.  In the book it was done by terrorists from a freighter off the coast. 

[DumbAss Tanker]

Not according to this:

"During nuclear tests in 1962, EMP disruptions were suffered aboard KC-135 photographic aircraft flying 300 km (190 mi) from the 410 kt (1,700 TJ) Bluegill Triple Prime and 410 kt (1,700 TJ) Kingfish detonations (48 and 95 km (30 and 59 mi) burst altitude, respectively)[27] but the vital aircraft electronics were far less sophisticated than today and the aircraft were able to land safely."

You keep quoting that, but I don't think you're reading it very carefully or understanding it for what it really says.  "Observed effects" and "Slagging down the power grid" are about as much alike as a flashlight and the surface of the Sun.

[RonBush]

You keep quoting that, but I don't think you're reading it very carefully or understanding it for what it really says.  "Observed effects" and "Slagging down the power grid" are about as much alike as a flashlight and the surface of the Sun.

You might be correct.  I hope you are correct.

[DumbAss Tanker]

A level of EMP far below what it would take to catastrophically damage the grid would knock out most consumer and business electronics, including post-1970s vehicle ignition systems.  Older vehicles with points ignition would be largely unfazed. 

Effects on aircraft would vary dramatically, but the the effect on the communications net they rely upon would mean that it would be a very, very bad day to be on a commercial plane in flight, even if the engines kept working and there were good analog back-up systems for the controls, because landing it anywhere would be completely chaotic.

That's what I was talking about when I said the effects on the grid would be the least of the problem.

[TVDOC]

Based on the technical papers that I've read on this subjest, such an attack would be unlikely.  Several of the reasons stated above are quite valid, specifically, that such a device would have to be precisely designed to maximize the EMP effect, and such a detonation would require a device with a yield in the 50 to 100 megaton range.

It should be noted that a thermonuclear device of this size was only test-detonated once, by the USSR, back in the '60's, and following that test, even their physicists determined such a yield to be unstable and impractical from both a tactical and strategic point of view, not to mention that the physical size and weight of a device of this size exceeds the capability of all but the largest of boosters.  The Soviets built it primarily for its political effect.

Then comes the targeting.....in order to be effective across the entire Continental US, the detonation would have to occur in the top level of the troposphere (between 150,000 and 180,000 feet, over central Kansas).  The critical altitude varies hour to hour depending on the conditions there, specifically the ionization level.  It would be a constantly moving target.......too high, and the EMP is reflected off the ionosphere, and dissipated toward space.....too low, and the effect is diffused by the molecular density of the atmosphere, which would act as a lens, concentrating  the EMP into a relatively small area.

In most of the studies commissioned in this area, the primary concern seems to be the effect from multiple airbursts detonating on various targets around the country, not  a single event specifically for EMP purposes.

It's not that it's impossible.....it just isn't really practical, and well beyond the capabilities of any nuclear power outside of ourselves and the Russians......even the Chinese don't have this kind of nuclear sophistication.

doc

[DumbAss Tanker]

Thanks, doc, that's all very consistent with my reading on it as well.

[JohnnyReb]

TVDOC....I believe I read somewhere that the Russian scientists calculated that a bomb larger 50 megatons was counter productive as a device of distruction. Something about the atmosphere acting as a buffer reflecting the explosive power back down upon itself negating any advantages of building bombs bigger than that.

ETA: I think I'm wrong. I believe it would blow a hole in the atmosphere allowing the explosive power escape into space....I'm going to have to Nadin this.

[TVDOC]

TVDOC....I believe I read somewhere that the Russian scientists calculated that a bomb larger 50 megatons was counter productive as a device of distruction. Something about the atmosphere acting as a buffer reflecting the explosive power back down upon itself negating any advantages of building bombs bigger than that.

ETA: I think I'm wrong. I believe it would blow a hole in the atmosphere allowing the explosive power escape into space....I'm going to have to Nadin this.

Theoretically, thermonuclear blasts larger than 50 megatons would simply create a significantly larger fireball and ground blast effect.  The fireball will continue to rise until it runs out of nuclear fuel or atmosphere (whichever comes first).....at which point it simply dissipates and combines with normal atmospheric contents plus ground debris to create downwind fallout.  Since a fusion reaction fireball vaporizes everything in it's path, the atmosphere would have little effect on its rise except for velocity.

Again, based on the limited release of Russian engineering data on that test, it appears that the determination was reached that such devices were "overkill", and the USSR's (limited) nuclear weapons research funding would be better spent on devices of a more tactical nature.  The second (and perhaps more important) result of the test was that detonations of this size create vast amounts of fallout at very high altitudes....capable of encircling the planet and coming back to "haunt" those who triggered the blast in the first place.

In somewhat simplistic terms, why build a few huge bombs when your adversary has 5,000 smaller weapons aimed at you.....after about one megaton the difference in effect becomes academic, rather than militarily advantageous.

doc

[RonBush]

Rumsfeld Warns of Iran, N. Korea Electromagnetic Pulse Attack

 http://www.newsmax.com/Headline/Donald-Rumsfeld-book-Iran/2011/02/13/id/385889

[DumbAss Tanker]

In somewhat simplistic terms, why build a few huge bombs when your adversary has 5,000 smaller weapons aimed at you.....after about one megaton the difference in effect becomes academic, rather than militarily advantageous.

doc

Yes; another way to look at this is to realize that relatively small amounts explosive placed in many separate, carefully-chosen locations can demolish an entire large and structurally-sound building, easily reducing it to a rubble pile.  The same net amount of explosive, placed in one mass and detonated within the building, will only cause severe damage without coming anywhere close to bringing down the structure. 

Scaling that up to nukes, a single 100 KT weapon will do a lot less net damage than 5 20 KT weapons hitting over a wider area.

Ron, worry yourself about it all you want, nobody who actually knows much about it regards it as a more pressing issue than a dozen much more immediate threats.  It would also behoove you to think a bit more critically about the possible agendas of people making dire warnings about it. 

[RonBush]

Ron, worry yourself about it all you want, nobody who actually knows much about it regards it as a more pressing issue than a dozen much more immediate threats.  It would also behoove you to think a bit more critically about the possible agendas of people making dire warnings about it.

You may be right.  As I said, I am no expert on this.  Several of you seem to have read more about it than I have.  I didn't get into this discussion to win a debate.  I am just curious and now I would like to figure this out.  Think of me as asking challenging questions in an attempt to learn more.

My interest in this has gotten stronger since I read part of " One Second After" by Forstchen.  This is part of what wikipedia says: "The book was cited on the floor of Congress and before the House Armed Services Committee by Congressman Roscoe Bartlett (R-MD), chair of the House Committee tasked to evaluate EMP weapons, as a realistic portrayal of the potential damage rendered by an EMP attack on the continental United States."

I don't know anything about Congressman Roscoe Bartlett (R-MD) or what his motives might be.  Does he have some political motive to be misleading?

[DumbAss Tanker]

Bartlett, I haven't any knowledge; I was thinking more of Rumsfeld, who never met an expensive aerospace program he didn't like, while being rather too slow off the mark in armoring ground combat vehicles.  Forstchen of course is a fiction writer, not a bad one at all, but they all stretch any scientific or engineering foundations in their stories to make the plot work, they don't shrink the plot to fit the feasible reality, whether they admit to it or not.

[TVDOC]

The DoD (and several other "alphabet" agencies) "war game" these scenarios all the time........that's their job........doesn't make any of them possible, or even probable.  Their function (and congressional oversight of this effort) is to make certain that the US is ready to meet all threats, likely or not.  Much of what they consider is pure science fiction, however, occasionally fiction becomes reality.

When it comes down to infrastructure vulnerability, specifically our national power grid.......I'd posit that we are far more likely to suffer a "cyberattack" than an EMP weapon.  Such an attack is much easier, cost one hell of a lot less, and is possible with technology already in the hands of most of our third-world enemies.....and can be nearly impossible to trace.

ANY nuclear detonation has a "radiation signature" left in the fallout by the fissionable materials used in the device.....that signature can be immediately traced back to the country of origin, the weapon manufacturing plant, and even down to the mine from which the ore was extracted.  Anonymity isn't possible.

Cyber warfare is much more subtle.

doc