New File Added: EMP Effects Notebook

[isopsycho]

Originally Posted by RayG IA

Did I understand that the optimum height for detonating a HEMP weapon is 26km? or 15miles? That is much lower than I had heard before.

If that's correct, then doesn't that mean the effect is limited to about 350 miles from ground zero?

The wording may be a little poor (he is still refining his book) but what it actually is pointing at is the source region is at 26 km, any weapon detonated above this distance will create an EMP at maximum effect. Its the gamma rays that travel down to this 26 km point and make that fully deposit into knocking electrons which in turn make that quick turn to create that EM pulse. This electron/gamma interaction zone is know as the source region which is dependent on the atmosphere composition and especially density (atmosphere increases in density exponentially so the region is very definitive instead of a linear one).

So effectively what he is saying is the source region is at 26 km. The higher the weapon detonation, the larger the source region will be and the larger the EMP coverage area. However, it takes more gammas to create this source region because the disperse spherically outward at 1/4pir^2, so the bigger the weapon in kilotons gives more gammas to provide in saturating the source region.

[RayG IA]

I think the wording is fine, it my lack of knowledge and fuzzy mind that's causing the difficulty.

Based on what you said in the last reply, for any given size weapon, the higher the detonation is above 26km the larger the source region will be and therefore the EMP affect, but the EMP affect would be weaker because the gamma radiation would be spread out over a greater source region area. Is that correct? If so, what does that mean from a practical point of view?

What is the effect on the ground likely to be from a 10kt detonation at 26km vs 100km.

A 26km denonation over Philly would affect an area that included Boston, all of the state of NY, PA, CT, RI, ML, NJ and DE over to Cleveland, 3/4 of VA and south to the Raleigh/Durham area. This assume a line of sight area with a radius of about 576km or 350mi.

[isopsycho]

Originally Posted by RayG IA

I think the wording is fine, it my lack of knowledge and fuzzy mind that's causing the difficulty.

Based on what you said in the last reply, for any given size weapon, the higher the detonation is above 26km the larger the source region will be and therefore the EMP affect, but the EMP affect would be weaker because the gamma radiation would be spread out over a greater source region area. Is that correct? If so, what does that mean from a practical point of view?

You got it, the gamma rays determine how big (surface area covered in the atmosphere) the source region will be. Now the max an EMP will be can not be greater than the conductivity of the air (30-40,000 volts/m depending on which author you read and which air chemistry assumptions they make). So the yield increase just gives you a better chance of getting to saturation.

Originally Posted by RayG IA

What is the effect on the ground likely to be from a 10kt detonation at 26km vs 100km.

A 10 kt won't do much at 100 km, now at 26 km there will be a small pulse but the weapon needs to be above the 26km so the gammas can scatter in a non-uniform fashion otherwise the more uniform the burst is the electric charges created cancel each other out (equal charge spaced out evenly in a sphere cancel out). This is why there is only and EMP effect in high altitude and surface, everything in between is closer to a uniform spherical burst.

Originally Posted by RayG IA

A 26km denonation over Philly would affect an area that included Boston, all of the state of NY, PA, CT, RI, ML, NJ and DE over to Cleveland, 3/4 of VA and south to the Raleigh/Durham area. This assume a line of sight area with a radius of about 576km or 350mi.

The EMP effect (for HEMP only) is also governed by the earth's magnetic field when it comes to placing your shot optimally (besides getting the yield and altitude maximized). The earth's mag field determines the arcing of the electrons. Unfortunately, most of the US is in a perfect angle being on and close to the 45 parallel. So even though they could detonate directly above you the max field actually won't hit you.

I'm going to see if I can find some unclassified EMP field pictures displayed over the US for an example.

[RayG IA]

That would be great.

If a small device would create only a small pulse and based on what we know about the countries that have nuclear weapons, which countries have large enough weapons to create a large pulse that would create a widespread SHTF situation? It was my understanding that most, if not all, of the new comers to nuclear weapons technology were making smaller weapons.

How big of a weapon does it take to create the large pulse that would create a widespread SHTF situation? and at what altitude would be the optimal for detonation? and what area would be affected?

I read a story, Light Out maybe, where one device detonated over the central US would cause a nationwide problem, is that likely?

If you are on the fringe of the EMP affected area, is the pulse weaker?

Is it true that a battery operated radio with a short antenna would not be affected?

Sorry for all of the questions, but there is so much "pseudo information" available, I never know what to believe.

[isopsycho]

Originally Posted by RayG IA

That would be great.

If a small device would create only a small pulse and based on what we know about the countries that have nuclear weapons, which countries have large enough weapons to create a large pulse that would create a widespread SHTF situation? It was my understanding that most, if not all, of the new comers to nuclear weapons technology were making smaller weapons.

How big of a weapon does it take to create the large pulse that would create a widespread SHTF situation? and at what altitude would be the optimal for detonation? and what area would be affected?

I read a story, Light Out maybe, where one device detonated over the central US would cause a nationwide problem, is that likely?

If you are on the fringe of the EMP affected area, is the pulse weaker?

Is it true that a battery operated radio with a short antenna would not be affected?

Sorry for all of the questions, but there is so much "pseudo information" available, I never know what to believe.

All your questions are valid and your right, most information on EMP is hearsay with no science to back it up. I'm here to say I can back up what I say with math and some testable scenarios.

The average yield of a 1st world weapon system is about 450 KT, the Hiroshima was about 15-22 KT (depends where you find what facts). The weapon systems North Korea and Iran are fielding are no where close to 450 KT just because they do not have the design maturity and infrastructure to build them (yet). The maximum gun-tube type weapon will get you about 20 KT (Hiroshima) and a basic implosion device (Nagasaki) about 18-30 KT. If the nuke bent nation improves in the design and efficiency of the weapon they probably could get up to about 150 KT (implosion plutonium based weapon with secondary). Now with that 150 KT weapon detonated over the US it would wreck some havoc. I don't know the EMP spread distance off the top of my head, I use a program called HEMPTAPS (High Altitude EMP Test And something Simulator). almost all of the out put is classified due to the weapon systems it has for its selection. However, there is an unclassified variable yield weapon selection that I'm using for my research (so I can publish without it going underground). Of the test runs that I've done with that the E1 and E2 pulses don't carry very far - 200-300 KM from GZ, after that the coupling needs assistance like antennas to get any real current loads on systems. Now the scary thing is the E3 pulse that comes last, its wave lengths are well matched and will couple with every power line, power transfer, and transformer in the majority of the US. This is where you get your big damage. The entire US without power for at least several weeks if everything goes right (and it won't, just look at Katrina planning/reaction capability).

Hope that helps some. The real problem in studying EMP is that to get a pulse that is anywhere near a nuclear generated one, you need a nuke. Nothing else is close in speed or magnitude. So the engineers and scientists use some math to determine the EMP pulse peak, mathematically propagate it a distance, convert to a coupling current value and use it as the current value to zap electronics. Its a stats game now by taking many different orientations of the current zap point on the tested device and testing over and over to find out what gets burned out. Its cost prohibitive and only gives you a statistical average.

[Grevlin]

Originally Posted by isopsycho

Of the test runs that I've done with that the E1 and E2 pulses don't carry very far - 200-300 KM from GZ, after that the coupling needs assistance like antennas to get any real current loads on systems. Now the scary thing is the E3 pulse that comes last, its wave lengths are well matched and will couple with every power line, power transfer, and transformer in the majority of the US. This is where you get your big damage. The entire US without power for at least several weeks if everything goes right (and it won't, just look at Katrina planning/reaction capability).

My instinct tells me that may be a bit of a best-case scenario, but even several weeks without power would rip us apart.

Iso,

As the member quickly becoming the EMP expert, (IMO) how do you feel about the chances of an EMP attack, and long term effects of one?

and

Are you prepping for one, or plan to?

[isopsycho]

Originally Posted by Grevlin

Iso,

As the member quickly becoming the EMP expert, (IMO) how do you feel about the chances of an EMP attack, and long term effects of one?

and

Are you prepping for one, or plan to?

I appreciate the vote of confidence, I'll let you know if I pass my thesis defense before claiming that title Really though, the Nuclear Engineering program here at the Air Force Institute of Technology is quiet good, its 75% weapon based and only 25% reactors, so I'm only Holiday Inn Express dangerous in doing reactor stuff

My estimate of an EMP attack on the US: its a difficult plan to execute without a solid base in ICBM and two stage nuclear weapon technology (plutonium implosion and 2nd stage uranium boosting). That leaves only a couple nations capable of delivering this threat: China, former USSR and maybe North Korea and Iran if you give them some benefits of the doubt (I doubt their ICBM capability so they would have to go clandestine container launch). If that happens and they manage to get a single EMP effective weapon to work as planned: VERY dangerous outcome. Just look at the previous power outage caused by the solar spike back in 1993-4 in Canada and the power grid failure in the US a few years back. It caused major problems and we had communications and reserve power systems. In an EMP you won't have those, no general comms, no power sources without repair parts. Given how fast people can get panicked and start rioting its a situation I can't stop wondering about.
My preparing mind set is to prepare for all the eventualities that lead to complete social breakdown. How we get there is the contingency details I work through. For EMP, I'm basically set with reserve two-way radios, emergency channel receivers, back up power systems (solar, gas and chemical) and a complete computer system to access my enormous library of information.

[isopsycho]

OK, I found some EMP pictures from the internet. The pics show what a max peak weapon yield would look like in region coverage. The volts per meter (the actual electric field coupling with what ever is out there) is messed up, the values are using old air chemistry data showing a saturation limit of 50,000 v/m, not likely (most likely using the old 1 MT bomb estimates used to brief congress). The normal range for a 450KT yield weapon would be about 5000V/m, a 100 KT would be about 1200 V/m. You can scale it mentally using a 1/r squared tapering.

The weird contour lines depicts the 'lensing effect of the curved magnetic field versus the burst point.

[JimRobert]

Can one ground a Faraday cage kept indoors to something internal, e.g. I have conduit with my electrical wiring. What about wall outlets? Anyway to use them?

[JimRobert]

Great... so all the fruitcakes on the east and west coasts, according to your map, and who are the main cause of our military weakness, seem to get off with the least amount of impact. :-\

[isopsycho]

Originally Posted by JimRobert

Can one ground a Faraday cage kept indoors to something internal, e.g. I have conduit with my electrical wiring. What about wall outlets? Anyway to use them?

Yes, the shorter the path the better though. Oh, and the map shows 50% of the Peak EMP pulse, the peak is quite abit considering it pulses at about a few nano seconds So no one is really safe...

[JimRobert]

.... but doesn't have the science background, unfortunately! ("get it" in that I understand there is a real threat). First, isopsycho, I very much appreciate all your input (in fact, I just went out and sanded down the weld line, as best as possible, on my makeshift Faraday cage (steel garbage can). Hopefully, all this preparation will never be used, but better prepared than not, particularly with the (sorry for the political comment here) incompetent administration running the country.

Question for you: Now that I've got my little Faraday/garbage can ready (I took off the metal handles, which presumably could also act like an antenna?), the question is of grounding. I have a small APC UPS in my house for my computer. Could I simply run a line to that? I.e., as this has the three prong plug for the wall, would that be sufficient grounding?

You are to be commended for your help and comments. America was founded by people who believed in self-reliance and not being dependent. You fit well into that tradition. Thank you!!

[isopsycho]

Originally Posted by JimRobert

.... but doesn't have the science background, unfortunately! ("get it" in that I understand there is a real threat). First, isopsycho, I very much appreciate all your input (in fact, I just went out and sanded down the weld line, as best as possible, on my makeshift Faraday cage (steel garbage can). Hopefully, all this preparation will never be used, but better prepared than not, particularly with the (sorry for the political comment here) incompetent administration running the country.

Question for you: Now that I've got my little Faraday/garbage can ready (I took off the metal handles, which presumably could also act like an antenna?), the question is of grounding. I have a small APC UPS in my house for my computer. Could I simply run a line to that? I.e., as this has the three prong plug for the wall, would that be sufficient grounding?

You are to be commended for your help and comments. America was founded by people who believed in self-reliance and not being dependent. You fit well into that tradition. Thank you!!

Let me do some math on the grounding bit. I'm thinking the distance may be too much using the house ground line. Also, I need to go find the conductivity of a metal trash can, that will tell me allot about how the pulse will couple with it frequency wise (I have all this available here at the University )).

If you can give me the brand name or if it has the metal composition rating (something like 20% Zinc, 60% Aluminum and 20% Tin) that would help.

What I want to do is find the pulse coupling factor and skin depth of the EMP wave incident on the can and at the weld and corner points. Falls within my research so the tax payers shouldn't mind too much

[isopsycho]

Originally Posted by JimRobert

Great... so all the fruitcakes on the east and west coasts, according to your map, and who are the main cause of our military weakness, seem to get off with the least amount of impact. :-\

Oh, I just remembered! That is just ONE emp/nuke, the enemy would use 2-3 to get good coverage (I never under estimate them). So the east and west would be just as hard hit.

[JimRobert]

Thank you. I'll call them in the morning. Nothing indicated on the can, other than it's a 31 gal galvanized can from Behrens Mfr, in Winona, MN. I'll give them a shout in the morning and report back. Meanwhile, having info like this for those of us not gifted in the sciences like you will be a great help, which I will pass on to others. I was also trying to find an article I saved about how Iranian scientists are much further along than thought with miniaturization of warheads, but I can't find it. If I do, I'll send you the link.

Once again, thanks, and keep up the great work!

Kind regards, Jim