Deprivation or not.

[mekender]

I hate to say it, but I think a nuclear attack against the US is inevitable. I just hope it's a light enough blow that it serves as a wakeup call, instead of a knockout. There are still enough competent Americans to make very fast progress on the defense front, once we put aside childish notions. It might be an occasion for hanging those who stood down our defenses in the first place.

I am surprised it hasnt happened yet... and i agree, i think it is only a matter of time...

my suspicions are that the attack will happen in one of a few places... NYC, DC, Seattle, Norfolk, Jacksonville FL, Miami, San Diago, LA, or perhaps Houston...

from a tactical standpoint, Norfolk, DC, Jacksonville and San Diego are the most likely... from a loss of life standpoint, pick any of the others...

but i would bet good money that it will be a coastal city and that it would be delivered by boat...

[mekender]

chris, some of this report seems to disagree with you, at least in part

http://www.empcommission.org/docs/A2473 ... on-7MB.pdf

[postmanone]

I have read other reports that show EMP would be devasting to the US; Here a a few;
And lets say it only last one month, you really think the people of the United States would react well to very little to no electical power? Note what happened today, cyber attack on our grid, question--why?
Anyway other points of view.

In testimony to the 1997 U.S. Congressional Hearings, “Threats Posed by Electromagnetic Pulse to U.S. Military Systems and Civilian Infrastructure; House of Representatives, Committee on National Security, Military Research and Development Subcommittee, Washington, DC, Wednesday, July 16, 1997” (Hon. Curt Weldon, Chairman of Military Research and Development Subcommittee), Dr. George W. Ullrich, the Deputy Director of the U.S. Department of Defense's Defense Special Weapons Agency, DSWA (now the Defence Threat Reduction Agency, DTRA) stated:

“Starfish Prime, a 1.4 megaton device, was detonated at an altitude of 400 kilometers over Johnston Island. Failures of electronic systems resulted in Hawaii, 1,300 kilometers away from the detonation. Street lights and fuzes failed on Oahu and telephone service was disrupted on the island of Kauai. Subsequent tests with lower yield devices [410 kt Kingfish at 95 km altitude, 410 kt Bluegill at 48 km altitude caused EMP problems, 7 kt Checkmate at 147 km] produced electronic upsets on an instrumentation aircraft [the KC-135 that filmed the tests from above the clouds] that was approximately 300 kilometers away from the detonations.

“Soviet scientists had similar experiences during their atmospheric test program. In one test, all protective devices in overhead communications lines were damaged at distances out to 500 kilometers; the same event saw a 1,000 kilometer segment of power line shut down by these effects. Failures in transmission lines, breakdowns of power supplies, and communications outages were wide-spread.”
---------------------------------------------------------------------------------------

The first EMP signal comes from the prompt gamma rays of fission and gamma rays released within the bomb due to the inelastic scatter of neutrons with the atoms of the weapon. For a fission weapon, about 3.5% of the total energy emerges as prompt gamma rays, and this is added to by the gamma rays due to inelastic neutron scatter in the bomb. But despite their high energy (typically 2 MeV), most of these gamma rays are absorbed by the weapons materials, and don't escape from the bomb casing. Typically only 0.1-0.5% of the bomb energy is actually radiated as prompt gamma rays (the lower figure applying to massive, old fashioned high-yield Teller-Ulam multimegaton thermonuclear weapons with thick outer casings, and the high figure to lightweight, low-yield weapons, with relatively thin outer casings). The next part of the EMP from a space burst comes from inelastic scatter of neutrons as they hit air molecules. Then, after those neutrons are slowed down a lot by successive inelastic scattering in the air (releasing gamma rays each time), they are finally captured by the nuclei of nitrogen atoms, which causes gamma rays to be emitted and a further EMP signal which adds to the gamma rays from decaying fission product debris. Finally, you get an EMP signal at 1-10 seconds from the magnetohydrodynamic (MHD) mechanism, where the ionized fireball expansion pushes out the earth's magnetic field (which can't enter an electrically-conductive, ionized region) with a frequency of less than 1 Hertz, and then the auroral motion of charged particles from the detonation (spiralling along the earth's magnetic field between conjugate points in opposite magnetic hemispheres) constitutes another motion of charge (i.e. an time-varying electric current) which sends out a final EMP at extremely low frequencies, typically 0.01 Hertz. These extremely low frequencies, unlike the high frequencies, can penetrate substantial depths underground, where they can induce substantial electric currents in very long (over 100 km long) buried cables.
http://glasstone.blogspot.com/2006/03/e ... space.html

[Rich]

Keep in mind, many of these reports including government reports, are really meant to influence ongoing debates. EMP damage estimates commissioned by people who stand to get money and/or power by receiving contracts to harden facilities will always err towards the most destructive scenarios, while those who wish to see a smaller military and more peaceful world will probably stress the opposite.

Read as much as you can find about who commissions the report, and do as much of the math involved as you can, and then draw your own conclusions.

You will probably wind up as confused as I often am when all is said and done, and will probably read these reports with a jaundiced eye as I often do.

I've sat in as an observer when a couple of civilian government reports were being prepared, and can tell you that it reminded me of sausage making. One was rewritten about six times before it said what the sponsor wanted it to say.

[Aaron]

the effect that would happen on power lines would basically be like a series of ever intensifying waves of electrons hammering down the lines into whatever they could... the end result would either be a total loss of function at transfer stations or an overload at one of the stepping stations... worst case would be an overload at a nuke plant that killed their ability to drop the safety rods leading to a meltdown...

now i suspect that much has changed in the research since the articles i read were written which was probably at least 15 years ago... so who knows...

Uh, not so much. Close to the epicenter of a high energy event you might get some neat special effects from the electrical grid, but only if it was really big and really close. There are so many fuses, breakers, manual and automatic cut outs, etc in the electrical grid that any damage would be highly localized.

Also, no worries on the nuke plants. First off, most of the plants operating here in the states would have to be very expertly coaxed into melting down. It's a self regulating thermal exchange, as core heat goes up, power goes down, thus heat goes down. And you can't really loose the ability to scram (drop control rods) a reactor. You can loose the ability to keep them up, any loss of power to the control system will de-energize the circuit that keeps the rods in place, they fall, reactor go sleepy time (I'm quoting that last bit) whether you want it to or not.

[mekender]

I could go on about how pathetic, inadequate, and how much of a mess security is for both major telecommunications, and major electric utilities.

However, I cannot, and will not, for reasons of contract requirements and professional ethis.

now that i could totally agree with you on... the level of incompetence is STAGGERING

[postmanone]

Chris thanks for the detailed information. In retrospect I would have thought if a EMP bomb had that ability of killing off all electric stuff, we would have been hit by now. I was reviewing my owners manuel for my Toyota truck and it looks like the computer for the engine is in a steel box and that is inside the vehicle surrounded again by steel frame, firewall, and the last steel stucture is the body itself. I can see the only thing that could get fried would be my radio since it has a antenna's line directly to the radio itself. Now that would suck, no Rock and Roll? That would be mean.
Question, what do you think would happen if a nuke was set off in space, would that knock off our satellites?

[postmanone]

Chris here is another opinion,( an engineer) that reviewd your post. I wanted to get as many people, I could that knows the EMP and know what is fact and what is not; Here is his response;

Well, it seems to be a fairly good analysis but with a few apparent errors.

I don't know where they get the picoradian figure from. The initial detonation should be modeled as a point source, and then take the total wattage and treat the power density with distance as a true omnidirectional sphere.

Also, the real destruction isn't to small compact handheld devices. It is, instead, to anything with protruding wires, which collect the EMP and concentrate it. For example, I can blow up stuff with an HF transmitter if enough RF energy is coupled into long wires approaching 1/4 wavelength which then feed something that is rather vulnerable to the absorbed energy, such as something close to an ideal impedance match (which is the impedance where maximum power transfer occurs).

Almost any kind of grounding or shielding makes high level airburst moot; and any real deliberate hardening or shielding will protect against low level airburst.

True, mostly.

A computers chassis alone is enough to shield against high level airburst. If it's inside most homes with a good ground and a good surge protector, low level airburst wouldn't get it either.
Yes, except the network wires, power cord, speaker wires, monitor cable, keyboard and mouse cable, are all effectively antennas that will collect and deliver energy equal to the area they cover. A surge protector will stop a lot of the destructive energy, but not that which is induced in the ground wires between the protector and the wall socket, as that acts like part of an antenna system.

Most modern electronics are shielded against RF interference. That level of shielding, combined with being inside a vehicle or a dwelling will protect most devices.
This is correct. Inside a vehicle will protect most devices. Inside a wood frame dwelling, which is effectively transparent to RF energy, will not. Inside a steel and concrete with rebar and mesh building, will protect quite nicely, except for whatever comes in through the power and phone wires. Overhead telephone and electric lines are a very long antenna system to couple destructive levels of energy into even a well shielded building unless there is proper control of where these lines enter, and a path to shunt induced energy to ground at the demarcation point (point of entry). Underground lines are reasonably well sheilded because the soil will absorb most of the energy and very little will couple into the wiring. Fiber optic cable is not susceptible to EMP, although dangerous voltages can build up in the jacket if it has anything conductive in it (or on it - rain-wet exposed fiber cable can bring lighting in along the outside of the otherwise insulated jacket).


Also, the VAST majority of electrical devices aren't EMP sensitive at all; except for at the highest possible power levels. Electric motors, compressors, most home appliances etc... Not a problem.
True for resistance type loads. Electric motors CAN be damaged if they are at the end of a long electrical line. We see this all the time in the oil field from lightning near misses, which is the closest approximation to a nuclear EMP seen in the natural world. I see 40 horsepower 480 volt 3 phase NEMA D motors crispy crittered on a regular basis when installed this way. Proper grounding and correct use of lightning arrestors tend to stop this problem. The usual failure mode is insulation breakdown in the windings, and then once a winding shorts from an EMP event, the regular electrical input (a horsepower is 746 watts, and that translates to a LOT of heat) completes the meltdown the next time the motor is turned on.

Never mind any military hardware which is specifically radhard.
Usually true. Not *always* the case, but certainly often enough to say most should survive.


Just another example here:

To TEMPORARILY disable a standard vehicle with directed microwave energy or something similar (HERF), requires about 1000 watts effective radiated power in a 1/4 second burst, at 10 meters.


Depends on WHERE the energy is directed. From some angles it won't couple enough into the wiring to mess anything up. From some other angles if it gets a good clean waveguided path into the engine compartment and its wiring, a lot less energy than that can crispy critter something, depending on where or if it ends up focusing.
A 1kt explosion at 1cm is equal to 16,740,000,000,000 watts of radiated energy in that same 0.25 second burst (it won’t be much faster than that because of the attenuation of air).


Air attenuates but it doesn't lenghten the burst. The actual nuclear explosion burst is closer to 0.000002 seconds, or about 2 microseconds. That is a lot of energy in a very, very short time.

Only about 5% of that energy is in the EM wavelengths that cause damage to electronics; and that’s if the device is optimized specifically for creating EMP. Let us assume that is the case.

Good enough working assumption.

The largest of the deliberate EMP devices we know of was in the 50kt range; for an effective radiated power (pre-attenuation) is 2.5kt; or 41,850,000,000,000 in a quarter second burst (the longer the burst, the lower those numbers get by the way).


Except it isn't a quarter second burst. More like a couple of microseconds.

The inverse square law states that radiated power in a vacuum falls off at a rate proportional to the square of the distance. If we presume a 10km airburst, that would result in a received power at ground level, of approximately 400mw.

How to calculate. Take the peak radiated power, divide by the number of square meters at the surface of a sphere 10 km in radius.


4 • #PI • r² = #PI • d² So if r is 10 km, the surface area would be 1256.636 km^2, or 1,256,636,000 square meters (1 million square meters in a square kilometer). Dividing your radiated power by this yields 33,303.19997 watts per square meter. This is delivered in about a couple of microseconds, so while the *average* power over a quarter second is indeed very low, about 66 milliwatts, the peak power density and thus voltage, is quite high, more than what is needed to crispy critter all sorts of unprotected electronics. Assuming 233 ohms for a characteristic impedance of space, a 1 square meter spiderweb of wires and such will induce a current according to P=I^2*R. P/R=I^2. Plugging in 33,303.2 / 233= 142.93 amperes. E*I=P. E=P/I. Plugging in 33302 / 142.93 = 232.995 volts. Per effective square meter of area. Since most solid state devices pop at somewhat below this, indeed, unprotected devices will certainly get zapped. However, the total energy delivered is 33,303.2 / 500,000 joules since the duration is a couple of microseconds. This is quite a bit below the human body capacitance energy that ESD protection has to absorb without damage. Thus, if you keep you wires short, a lot of small devices ought to survive just fine.


Not megawatts, milliwatts.

This presumes a vacuum, with no shielding. That is essentially never the case in the real world.

Air is not a vacuum. In fact, air attenuates high energy radiation considerably. A 40% relative humidity 72 degree day attenuates those electronics harming frequencies by up to 80% per meter squared (as in 80% of the radiated energy falls off in the first meter, then 80% of the remaining the next meter etc...).

* citation needed. Attenuation depends on frequency. I have not experienced this level of attenuation and have run microwave links tens of miles. That level of attenuation would make police radar not work, for example. Longer wavelenghs have almost no real attenuation (well, it's measureable but not more than a percent or so over several miles). Proper unit of measure is dB per mile. 3dB per mile is massive attenuation. I would expect 80% loss per meter through heavy vegetation, but not through moist air. We don't even get 3dB per mile in a rainstorm.


Oh and that also presumes that all the energy were focused on one picoradian . In reality, energy distribution is omidirectional (though not equal in all directions).

If it were focused on one picoradian, then it would probably vaporize a tunnel most of the way through the earth. That is 10^-12 radian. A radian is about 57 degrees. A picoradian is 0.000000000057 degrees. A complete circle is 6.28 radians, so if that energy were focused into a picoradian, you would see 6.28/0.000000000057 110175438596.4912 times the energy density on that little narrow spot. This comes out to 3,669,194,666,666,666.667 watts per square meter "in the beam". The actual number of joules delivered would be 7.338.389.333.333 They wouldn't have to worry about EMP. It would just instantly vaporize anything in its path as most of the nuclear detonation energy would be focused on a tiny area like a laser spot. Most laser divergences are measured in milliradians, by the way.

Now, if we presumed a 100kt device (the largest device we could detonate at 10km without killing everyone on the ground) , that was somehow magically 100% efficient, in a completely focused beam, and attenuation was insignificant, we would still have an effective received power at ground level of about 16 watts.

Nope, more like 33 kilowatts. Per square meter. For only a couple of microseconds. It isn't the average power over a quarter second that does the damage. It is the instantaneous peak power that induces peak voltages and currents that cause solid state devices to quietly die with a whimper.

50 years ago, when vacuum tubes rules the world, and early transistors were being phased in, a few milliwatts of stray power would probably fry a lot of electronic devices. These days, not a chance.

Vacuum tubes tend to withstand all sorts of heavy duty pulses. It is solid state stuff that is mostly vulnerable. The tinier, the more vulnerable it is. But, the smaller size also presents less area for the EMP pulse to collect, which makes miniaturization sort of a wash.

You would have to create multi gigawatt air bursting EMP devices, with total conversion to HEEMF detonated at under 5km to get the kind of effects you are talking about.

Actually there are four common classes of "thing" that will die with relatively light EMP:

CRTs that aren't shielded, anything with vacuum tubes that isn't shielded, a lot of consumer audio equipment if it isn't shielded (most of it is now), and any kind of very sensitive receiver tuned into the microwave ranges or fundamental harmonics thereof that doesn't have an overload circuit.

CRTs themselves generally are not solid state. Now the circuit that drives the is, so the monitor circuitry might die but the picture tube itself would work fine when transplanted into an undamaged monitor. Vacuum tubes, same thing. No shielding required.

Consumer audio equipment, yes. The destruction would come in the speaker wires, the power cord, the patch cords to / from the various components. Same for consumer video gear - VCRs, high definition TV, etc. Microwave receivers, probably not because the destructive energy is broadband - white noise that spans a lot of spectrum. Unless the antenna were aimed right at the detonating nuke.
So a lot of cheap GPSes, cell phones, satellite phones, and satellite radio recievers will die

Probably not that many, due to the low overall collection area of these small devices. However, the much larger cell sites would likely die, so your cell phone would work but it would say "No Service".