Electro Magnetic Pulse

G

GIBBY

Joined
Oct 27, 2004
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How far from ground zero would an EMP affect electronics and for how long?


...GIBBY
 
I believe anything close enough to be affected would be destroyed anyway, which is why some theorize that a nuke exploding in the atmosphere would have a much greater effect somehow, but I am no physicist.
 
I suggest you don't waste your time and effort worrying about EMP. If you survive the blast EMP will be the very least of your concerns. If you are thinking about keeping a vehicle operational, though, consider getting yourself an older one that still has the breaker point ignition system rather than a computer controlled system. Get an old one, spend the money to have it fully restored and rebuilt, and then learn how to maintain it yourself. You will have the equivalent of a new vehicle, and you should have less money in it.
 
In 1997-98 something at least one of the town councils in Sweden aquired old non computerized used LADA vehicles for use by the home care groups (healthcare/medics driving around looking after the elderly still living at home) just in case the Y2K bug would make the newer vehicles freak out.
Its about the same thing with a difference, EMP will toast PASSIVE components as well. Even if you dont have a computer in the car you might have transistors in some applications and they are not affected by Y2K but by EMP.
 
Any electronics affected by EMP are destroyed. An EMP or nuclear burst that is airborne will affect more area. High enough, and the EMP could cover most all of the ConUS.
You can protect electronics using a faraday cage. EMP does not require a nuclear explosion. You can make an EMP bomb from items available from any home improvement store, but would need a plane for truely effective delivery(although, prior to 9-11, it was speculated firing one on the top of a high rise would be pretty bad, too).
 
The faraday cage is only effective when the electronics in question are completely isolated(ie. no power cord connected to the grid). That could get awfully complicated with breakers and ups' and what not.

We've all seen the examples of EMP's in movies(always a credible source) such as Ocean's 11 and War of the Worlds. In the latter, the solenoid was all that was fried in an 80's minivan. I wonder if that would work, assuming there are no computers to fry.
 
tyr_shadowblade said:
Depends on the source. The EMP generated by a tac-nuke (suitcase or portable launcher) probably wouldn't be too bad. EMP from an ICBM hitting a major city is difficult to determine as it has not yet happened, so any answer you recieve will be theoretical. I do not believe anyone studied the EMP effect of the primitive nukes deployed in Japan during WW2. Modern ICBMs are far more powerful.
Click to expand...

We have a pretty solid understanding, after 60 years of experiments and theoretical developments.

Much depends on whether it is a burst in space, in air, just above the ground, or on the ground. And then, there's the question of yield and design. It's a little too complex to give you reliable answers in a post on Bladeforums.

While the pulse or pulses are of short duration, they generally contain a great deal of energy at a wide range of frequencies. If the device is competently built, the operator wants to focus on the creation of EMP, and the device is 'delivered' (shall we say) properly -- it could cause a great deal of trouble across a very wide area.

Then there's protection. I quote: "The faraday cage is only effective when the electronics in question are completely isolated(ie. no power cord connected to the grid). That could get awfully complicated with breakers and ups' and what not." [NeverToSharp, this Thread, Post #8) The author has a solid understanding.

I also quote: "I believe anything close enough to be affected would be destroyed anyway." (Liam Ryan, this Thread, Post #3) Unfortunately, Mr. Ryan is incorrect. EMP usually reaches much further than the blast radius or the thermal effect radius.

I hope that doesn't sound too pessimistic. But you asked.

EDIT: Forgot to address duration. In many cases, the upset is brief -- often an SEU or single event upset. Something like a bit flip...it can be handled by re-setting or in some cases by the use of polling logic in appropriate circuits. In other cases, the transient voltage is so high that junctions are 'punched' -- essentially destroyed. That's a hard kill. The electronics won't come back until they are physically repaired or replaced. Generally, it depends on the intensity of the initial voltage spike.
 
Somewhere, many years ago, I recall reading that two H-bombs, properly located and detonated 40 miles up, would fry every unshielded p-n junction(virtually all electronic gear) in the continental US. This would be a bad thing.

Gordon
 
cjpgeyer said:
Any electronics affected by EMP are destroyed. An EMP or nuclear burst that is airborne will affect more area. High enough, and the EMP could cover most all of the ConUS.
You can protect electronics using a faraday cage. EMP does not require a nuclear explosion. You can make an EMP bomb from items available from any home improvement store, but would need a plane for truely effective delivery(although, prior to 9-11, it was speculated firing one on the top of a high rise would be pretty bad, too).
Click to expand...

It takes an extraordinary conventional explosion to generate a sufficiently powerful EMP. I know it has been done with a large fuel-air device, but that is all I have heard of with anything other than nuclear.
 
Then there's protection. I quote: "The faraday cage is only effective when the electronics in question are completely isolated(ie. no power cord connected to the grid). That could get awfully complicated with breakers and ups' and what not." [NeverToSharp said:
Yes!! I just got props from Einstein! I rock.

Thanks, OP.
Click to expand...
 
good reply old physics high altitude detonation of a nuclear weapon scares the crap out of me because at high altitude the compton effect releases piles of electrons toward the earth and the pulse will pretty much hit anything line of site from the explosion. if it was a high enough yield bomb i have heard 1 megaton would take out all of the usa if detonated in the right spot (have not done the math myself though).
 
lambertiana--watch the series FUTUREWEAPONS--they fry a car without a fuel bomb or a nuke..but they are using a testing device with a lot of power. I am not going to get any further into where the info is documented on EMP bombs at Home Depot, but the info IS(was..nod to the gatekeepers) out there.
A faraday cage would be useless without total isolation, that's the point. Any breach in any of the walls of sheilding would negate the type of sheilding needed. We are not talking about protecting your data stream frequencies here, or sheilding cable! :)
 
No one mentioned asteroids cause emp too.

From http://archives.cnn.com/2002/TECH/space/07/24/asteroid.nt7/index.html

"British MP Lembit Opik, who has been a strong voice behind the formation of Spaceguard UK which tracks objects in space, called for urgent preventative action."

"He said such an asteroid could cause tidal waves, massive fires, provoke volcanic activity and the "electromagnetic pulse would fry most of the electronics on earth."
 
tyr_shadowblade said:
I do not believe anyone studied the EMP effect of the primitive nukes deployed in Japan during WW2. Modern ICBMs are far more powerful.
Click to expand...

State of the art in Japan during WWII was vacuum tubes. Tubes can be more robust than semiconductors (transistors) during an EMP event - there is more than one reason that the avionics in B-52s are STILL hollow state today. If you're really interested in this, do a google search on "oxide layer" along with your EMP queries.

Or, read here for a decent overview of the engineering behind "hardened" circuitry:
http://en.wikipedia.org/wiki/Radiation_hardening

To make a long story short, once a transistor (either discrete or integrated onto a chip) is damaged or destroyed, it won't heal itself. It needs to be replaced. That means the ECU in your car, your laptop, your radios, TVs etc, would be at risk unless they were HEAVILY shielded during the EMP event. Consumer electronics basically aren't designed for this kind of survivability.

-tantalum
 
tantalum said:
State of the art in Japan during WWII was vacuum tubes. Tubes can be more robust than semiconductors (transistors) during an EMP event - there is more than one reason that the avionics in B-52s are STILL hollow state today. If you're really interested in this, do a google search on "oxide layer" along with your EMP queries.
-tantalum
Click to expand...

And all this time, I thought guitar geeks were the only ones who used tubes anymore! ;)
 
cjpgeyer said:
lambertiana--watch the series FUTUREWEAPONS--they fry a car without a fuel bomb or a nuke..but they are using a testing device with a lot of power. I am not going to get any further into where the info is documented on EMP bombs at Home Depot, but the info IS(was..nod to the gatekeepers) out there.
A faraday cage would be useless without total isolation, that's the point. Any breach in any of the walls of sheilding would negate the type of sheilding needed. We are not talking about protecting your data stream frequencies here, or sheilding cable! :)
Click to expand...

That episode was based on electronic devices coupled with a warhead. See this paper written by the guy behind the FutureWeapons episode:

http://www.abovetopsecret.com/pages/ebomb.html

To create an EMP solely by the use of conventional explosives does indeed take a very large explosion.
 
Yes, a conventional EMP device as stated in the article. I am discussing UNconventional, with a significantly lower yield, as reported by a part of our gov't, that set off in a high rise a building or two away from the stock exchange would crash it. That was the senario.
 
That is what makes it more of a threat. You don't need a trainload of TNT or a thermonuclear device to generate an EMP. With easily available technology, as indicated in that paper, you can make an EMP device that can be driven into place in a small car.
 
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