"National Plan for EMP Protection" article in ITEM Magazine

[Tom WA3KLR]

The latest issue of Interference Technology/ITEM magazine, a magazine devoted to electromagnetic compatibility, has the first part of a good 2-part article on Electromagnetic Pulse (EMP), protection, and the realities of the long-term aftermath of a real event.  The article is titled "A National Plan for EMP Protection".
I think this is the best concise writing I have seen on the subject along with some nitty-gritty info I haven’t read before.

The authors are Don White and Jerry Emanuelson.  Most of you who have been exposed or involved with EMI reduction/compliance in the past will probably recognize Don White’s name and Don White Consultants, a 30 year contributor and publisher of EMI books.

The link to Part I of the articles:

http://www.interferencetechnology.com/a-national-plan-for-emp-protection-part-1/

One illustration that was interesting to me is Figure 3, a graph of standard of living after the EMP event versus size of population groups.

[W3RSW]

Fairly comprehensive and well reasoned article on global EMP effects however all discussions and literature of this type assumes a hermetic, single factor cause and solution...   Yeah, 80dbv shielding, um hmm, in this case.

I'd like to see a time axis on figure 3.  Of course the author mentioned that population size and quality of life factors were rather fuzzy but indicative.

Well we know the gamma yield fraction of total yield was fairly accurate.

If EMP of the scope envisioned in the article actually occurred, it's pretty apparent from history, competing social systems and human nature that far more severe causes and effects will compound survival rates and 'life style.'

Mutual assured destruction will inevitably follow.
Far more than secondary radio waves induced from gamma rays will impact the average 'survivor.'  "Real nukes" with "real gamma rays" along with all other wavelengths (heat, UV, etc.), primary and secondary shock fronts, etc. will be interesting.  All those are mostly inverse square effects based on yield and distance.

So along the same socially instigated lines, I seriously doubt you'll ever see a space elevator.
Way to easy a terrorist or state instigated target.  There's been a couple of sci-fi stories about such along with the subsequent wrapping around the world a few times of the fallen elevator.

-Zillions of stories about life (or not) after major thermo-nuclear war.

But the EMP article does make one think.  Maybe my hollow state stuff will survive (but I won't?)

Better lay in a stock of those large low-mu tubes.  Better element spacing, donch'a know.  

[W3RSW]

Richard Rhodes excellent books cover a lot including EMP.
Both have been discussed on this board and probably will come up in a search.

"The Making of the Atomic Bomb," Simon and Schuster, N.Y., London, etc.
"Dark Sun," ditto.

Speaking of population survival vs. yield graphs, Rhodes relayed the point about the death ratio of populations, combatants and non-coms, historically in war.

Suffice to say, In thermonuclear war the percentage of fatalities is now 100%, all participants, out to the slant range determined only by bomb yield.  The exponential curve is the same.

The number, yield and subsequent transported radiation of devices in any other than very light exchange is sufficient to cover even the 'out in the country' survivalists.

[Opcom]

"Mutual assured destruction will inevitably follow."
Maybe not. Consider a sophisticated terrorist act in the future as being unlikely to start an atomic war.

I did not understand how much potential current is behind this 10KV/meter statement. Is it like static electricity or what? I can today string up a wire in the back yard 3 meters off the ground and measure the earth's electric field but I can' take any useful power from that.

Individuals can't do much about the big stuff but they can do for themselves if not too complacent and they stick to non-electronically controlled appliances, etc. just common sense. Exactly how much would it cost to install a whole house system? How about giving one's house the equivalent of a tinfoil hat? Faraday cages do not have to be made of cost prohibitive copper. Moving sensitive electronics into one special room for economy is possible if one can accept a life style change. At last! - children would have to use the computer in the family room where it can be supervised! I could see headphones sales going up too. Also, manufacturers could begin to include EMP rated filters in equipment's ports. High bandwidth ports could be optically coupled in case a solid device would have too much capacitance per line. My company makes protection devices.

besides the tubes.. heh. an old car with no computer would be good. There is no need for a 'classic'. Racing supply houses sell regular old ignition systems and they work on non-racing engines. With most of the other cars off the road, gas would not be too much an issue if the major infrastructure would be protected.

Not all modern electronics need be ruined. Things can be stored in metal enclosures until needed. They would have to be inspected and run a little while, periodically, due to natural decay when things sit. I have a "plastic radio station in a can", doesn't everyone?

The air force developed and successfully tested a 747 with a laser to destroy missiles in the launch phase with the idea that the warheads would then fall to earth in the same principality from which they had been launched. The government making cut-backs canceled the program as "wasteful and unproven" while videos clearly show it works. I think the aircraft is still mothballed somewhere. Not saying that is an answer, but saying there are many possible answers in addition to shielding.

Who can predict the future? Each person has been issued a deck of cards. It is up to individuals and families to stack the deck for their own advantage. Everyone ought to have two disaster plans. One is to leave the area to a pre-arranged location. The other is to shelter in place long term. And, a low standard of living is still 'living'. I think the city is a viable place although the rules of the game may change under conditions of such hardship. In an isolated case without a devastating war following, things have a good chance to return to a better state before too long.

[Tom WA3KLR]

A simplistic estimation of the maximum H field current strength is that when an electromagnetic wave travels out from the source through space the wave impedance (E field/H field) becomes asymptotic to 377 Ohms. 

Figure 2 shows E fields as large as 50,000 Volts/meter.  This would be a current field strength of 133 Amps/meter.

[KA0HCP]

The author is on shaky ground when he starts mixing geo-politics into what is supposed to be a technical article.

-MAD is inevitable: This assertion is unsupported.  Given that both the US and Russia have renounced that policy and each has reduced stockpiles by over 90% this seems highly unlikely.   Assuming that all nations will have the same reaction regardless of the strike scenario e.g. location, number, tonnage, altitude, etc is simplistic.

-Presently no nations hostile to the US have thermonuclear weapons.  Indeed, North Korea has not demonstrated the ability to get above 2kt yield, practically a 'fizzle".

The author gives the impression that US military electronics are hardened.  That may have been the case (mostly) thirty years ago, but not now.  One of the trade offs made in the early 1990's was the dropping of Milspec's for electronics in order to take advantage of COTS components and equipment.

The cost to harden even a portion of civil infrastructure would be huge.  A tremendous burden that would influence our economy and have to be made as an informed decision.  

Don't expect to see any major EMP protection in consumer or industrial devices any time soon.

The difficulty we have is discerning:
-Who is providing legitimate education for engineers, techs and government
-Who is buffing up their reputation and customer base
-Who is writing scare articles

[AB2EZ]

Putting aside related conspiracy theories...

To what extent do FCC part 15 rules that limit the emissions of electronic devices, particularly modern battery operated devices, also mitigate HEMP ingress/damage?

Stu

[KA0HCP]

Since an attacking warhead is an Intended Radiator, they must file for Part 15 Certification before beginning war operations. 

[W3RSW]

Pirates all.

[Steve - K4HX]

Even if they did, the enforcement is minimal, so any protection potentially achieved could be minimal.

Also, most filter designs in consumer electronics would do little to protect from EMP - they do not filter differential signals very well.

Putting aside related conspiracy theories...

To what extent do FCC part 15 rules that limit the emissions of electronic devices, particularly modern battery operated devices, also mitigate HEMP ingress/damage?

Stu

[K9PNP]

Since an attacking warhead is an Intended Radiator, they must file for Part 15 Certification before beginning war operations. 

Don't think they could get it past Part15.201(c).  Awfully hard to test things multiple times when they are designed to totally obliterate themselves in normal use.  And, since any nuclear device detonated in the atmosphere at an altitude such that it just causes EMP, would seem to me to be defined as something more than an Intended Radiator.  Therefore, it would need to be licensed which would really be a nightmare even to determine which service it would be licensed in.

The author is on shaky ground when he starts mixing geo-politics into what is supposed to be a technical article.

-MAD is inevitable: This assertion is unsupported.  Given that both the US and Russia have renounced that policy and each has reduced stockpiles by over 90% this seems highly unlikely.   Assuming that all nations will have the same reaction regardless of the strike scenario e.g. location, number, tonnage, altitude, etc is simplistic.   

IIRC, the studies done at the height of the Cold War could not agree on what would happen after somebody popped the  first nuke.  I believe the general theory held that it was up to the mental state of whomever the politician was that had the  launch authority.

And the notion that military electronics are hardened is, as noted, suspect.  Most tactical gear since 1970 has not been  done with any apparent reliability.  before then, the use of tubes in the receiver RF amp and the transmitter final appears to be one of the few things done.  Of course, those help when you transmit without an antenna or with the wrong antenna or have your receive antenna right next to an active transmitter antenna.

End of soap box.  Actually a reasonable article. 

[wa3dsp]

When you talk about EMP there are two things I think of and neither is a hostile nuclear blast. The sun is one and an asteroid collision is the other. Solar flares of sufficient magnitude directed squarely on the earth could cause a lot of damage particularly in the electrical grid. Either of these events in sufficient size would be far more devastating than a nuclear explosion.

So I think all hams should be encouraged to build a "fallout" screen room with all conductors in or out shielded for the most severe EMP. Actually if you have old tube equipment with no solid-state diodes you should be OK that is if you have anything to power it with! The majority of power company transformers would be toast. Better store  a few solar panels in your screen room. Then you have to worry if there is any sun to power it after the blast.

[Pete, WA2CWA]

Let's all just hide under the desk/table/chair/whatever and wait for all the all-clear signal. Anything else is a waste of energy.

[KB2WIG]

                                                             .

[Opcom]

Hiding defeats the purpose. Life is short enough and each special event is an opportunity for a new experience!

50KV/meter
133A/meter

Is there any simple answer to what pulse length and rise /fall time? (maybe I missed it)
Wouldn't the rise be short, and the fall slow due to some time constant related to this 377 Ohm impedance of the aether?

Considering only the electrical fun part of this, would it kill exposed persons directly under the source, shock them, heat them, cause an odd sensation, or nothing?

[Pete, WA2CWA]

Hiding defeats the purpose. Life is short enough and each special event is an opportunity for a new experience!

So is walking in front of a moving bus.

[Tom WA3KLR]

As far as waveforms and currents:

I found the MIL-STD-461E spec on the web and the RS105 portion is the radiated susceptibility transient electromagnetic field testing for NEMP hardening at:

http://snebulos.mit.edu/projects/reference/MIL-STD/

 The test waveform is a dual exponential waveform – in other words has a fast rise and a slower fall rate;
- rise time (between 10% and 90% points) between 1.8 ns and 2.8 ns (electric
field continuously increasing).
- full width half maximum (FWHM) pulse width equal to 23 ns + /- 5 ns.

I found a 19 page article on the web with some good information where the author talks about simulator performance versus NEMP standards:

http://www.ece.unm.edu/summa/notes/SSN/note538.pdf


The NEMP pulse is going to shock excite all metallic cables and structures of various dimensions and configurations and of various orientations relative to the polarity of the arriving wavefront; some more like open circuits and some more like short circuits. So the resulting voltages and currents can be of wide-ranging values and then will ring at their own resonant frequencies.

Another source on the web that can just be previewed - A Handbook for EMC Testing and Measurement, by David Morgan:

http://books.google.com/books?id=O7NYUnPFuSYC&printsec=frontcover#v=onepage&q&f=false

Page 194, section 10.4.4 “NEMP Induced Currents” has graphs showing some induced currents.
Figure 10.22 shows an example of current induced in a long overhead power line.  The peak value is 12,000 Amps with a half-current pulse width of about 1.5 microseconds.

Further down on the same page, figure 10.23 shows (with 50KV/meter field strength) current induced in 7.5 meter (24.6 feet) tall monopoles. This could be street lights or radio towers.  The peak value is 1200 Amps and rings at approximately 10 MHz., the quarter wave resonant frequency of the monopole.  (The Q is approximately 1.74!)

[Opcom]

Hiding defeats the purpose. Life is short enough and each special event is an opportunity for a new experience!

So is walking in front of a moving bus.

It's not about the outcome. There's a difference uniqueness between the two experiences. Nothing special about a common vehicle.

[DMOD]

The author gives the impression that US military electronics are hardened.  That may have been the case (mostly) thirty years ago, but not now.  One of the trade offs made in the early 1990's was the dropping of Milspec's for electronics in order to take advantage of COTS components and equipment.

During the later 90's and into the 2000's, we went back to hardening various Military components at great cost due to increasing threats from nations having advanced weapons or the potential to have WOMD's.

I say at great cost, because until that time, we had been replacing components with non radiation hardened components.

Phil - AC0OB - Former Nuclear Analyst for the Aerospace Industry

[KC2ZFA]

The test waveform is a dual exponential waveform – in other words has a fast rise and a slower fall rate;
- rise time (between 10% and 90% points) between 1.8 ns and 2.8 ns (electric
field continuously increasing).
- full width half maximum (FWHM) pulse width equal to 23 ns + /- 5 ns.

That's the voltage fed to the radiator and not the electric field of the pulse that is actually radiated.

[Tom WA3KLR]

KB4QAA,

Number of Nukes – U.S. and Russia

I don’t think that the warhead reduction is 90 %, 10 % of what there was.  I wish this were true.  I am using 1988 as the back reference of total inventories.  Referring to a Bulletin of the Atomic Scientists, the U.S. had 23,205 then and Russia had 36,538.  Now the U.S. has 7,700 and Russia 8,500.  This is a 73 % reduction or 27 % of what there was in 1988.  A couple years ago I knew the U.S. had around 33 % of what we used to.
- - - - - -


KC2ZFA,

MIL-STD-461E RS105 – After reviewing this spec., I still believe that the waveform specification I referenced above is for the field probe reading, not the generator output.  The generator output is monitored and recorded with a scope however.

[KC2ZFA]

strange...the EMP arises from time-dependent currents excited by the nuclear explosion. According to Maxwell's equations the radiated electromagnetic field is proportional to the time derivative of the time-dependent current that created it. Which means that the EMP propagating in the free space between the source region and the measurement location cannot have a spectrum with a non-zero DC component.

The only case where you can have a propagating electromagnetic pulse that looks like the purported EMP pulse shape (whose spectrum has a non-zero DC component) is in a TEM line.

[Tom WA3KLR]

While we’re all waiting with baited breath for Part 2 of the “National Plan for EMP Protection” article, Interference Technology (ITEM) has published a related article titled “High Power Electromagnetic (HPEM) Threats to the Smart Grid”

http://www.interferencetechnology.com/high-power-electromagnetic-hpem-threats-to-the-smart-grid/

[Tom WA3KLR]

Part II “A National Plan for EMP Protection (Part 2) – Protection of Buildings”
is finally published.

 “Part 2 of the article presents methods and techniques for EMP protection of buildings, solar rooftops and other structures. As such, Part 2 covers details of shielding, bonding, grounding, and cable or device surge suppression and filtering. These apply to structures from sheds and rooms to small and large homes, and to commercial and industrial buildings less than about five floors in height.”

http://www.interferencetechnology.com/national-plan-emp-protection-part-2-protection-buildings/

[flintstone mop]

There was a lot of chatter going on if the event would affect electronics that were turned off. Anything in operation that wasn't "hardened" and our electrical grid would be extensively damaged.
Tube equipment would be spared?
Any way we would be in the dark ages for years as generating plants buy new high voltage transformers. $1 million a piece and special order. Not made in the USA.
Fred