EMP Attacks on 1st world nation like the US

[kcran567]

Nations like N. Korea, Iran, and groups like ISIS (which did power grid attacks in Yemen) and possibly even Russia (as part of an opening phase) could use this to cripple a large nation like the US.

A 20 mile high burst from a nuclear tipped Scud fired from a freighter off the east/west coast is the typical scenario.

Any knowledgeable experts here on this forum to verify this as a real threat or any defense against this, or is overblown threat to get money to harden the power grid?

Very cheap (relatively) to destroy a country in asymmetric warfare.

 

[riggerrob]

You don't need nuclear bombs to build EMPs.
Since the 1960s, the USA and USSR have been using non-nuclear EMP simulators to test shielding on military electronics. Old-school EMP simulators include a pile of capacitor plates. After sufficient electricity has been stored, they use explosives to collapse the stack of capacitors and generate a massive electro-magnetic pulse.
Funny how the USA and USSR only published their results during the 1960s??????

More recently (2015?) Aviation and Space Weekly reported that the USAF was planning a new generation of drones with reusable EMP generators to cripple defensive electronics.

Depending upon your target, you could simply jam the signal by broadcasting noise on the same frequency at very high wattage. Transmission wattage drives the thickness, weight and expense of defensive shielding.

You don't even need aircraft to deliver an EMP generator. With sufficient planning, you could deliver an EMP by torpedo or boat or truck or passive mine or courier or any delivery method you could imagine.

 

[sublight_]

By "cripple" you mean not work until I reboot my PC? Modern electronics are vulnerable to EMP disruptions but are near impossible to permanently damage.

 

[Orionblamblam]

A 20-mile altitude is pretty low for such things. For starters, the EMP is really only good out to the visible horizon, which is much shorter at 20 miles than at, say, 300. Second, at that low altitude it's by no means certain that there actually *will* be an EMP. You have to rain gamma rays *down* onto the very thin upper atmosphere to get the Compton Effect running right. At that altitude, the EMP *might* be somewhat shorted out by the relatively thick air.

 

[kcran567]

So a large scale (nationwide) attack that knocks out the power grid sending the civilian population back to the 1800s seems like fantasy?

There are a few individuals claiming The whole power grid is vulnerable to one high altitude nuclear blast.

An accurate attack, i.e. EMP drones, to take out a military target is more reality based?

 

[Brickmuppet]

So a large scale (nationwide) attack that knocks out the power grid sending the civilian population back to the 1800s seems like fantasy?

There are a few individuals claiming The whole power grid is vulnerable to one high altitude nuclear blast.

An accurate attack, i.e. EMP drones, to take out a military target is more reality based?

A nuclear EMP above a certain altitude (I think, its around 35 niles) can take out everything that's not hardened out to the visible horizon. Note that the higher one goes the more yield is needed to get certain effects. The Russians popped off a 300 kiloton nuke at an altitude of 290 kilometers from their Kasputin Yar test site. This melted underground power cables, set fire to generators shut down a power plant and blew out every breaker and fuse in a 570 kilometer long telecom line.

There is an overview of this test here...

http://www.futurescience.com/emp/test184.html

There is an extensive article on the damage to the telecom line at IEEE

https://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=736221

Here is a talk including James Woolsey and Henry Cooper (who some of you will remember from his work with HIGH FRONTIER) who, in 2013, held forth on the matter for a bit over an hour.

https://www.youtube.com/watch?v=iBfALe8X9C8

Amongst the things discussed is the possibility of multiple cascading Fukishimas.

 

[RyanC]

The Russians popped off a 300 kiloton nuke at an altitude of 290 kilometers from their Kasputin Yar test site. This melted underground power cables, set fire to generators shut down a power plant and blew out every breaker and fuse in a 570 kilometer long telecom line.

And why did that happen?

here's a hint:

remote area.

extremely long runs of power/telecommunications lines on the order of hundreds of miles due to remoteness.

This enables an extremely large EMP to build up due to the power lines and telco lines acting as giant antennas hundreds of miles long, causing said "fun".

 

[Orionblamblam]

So a large scale (nationwide) attack that knocks out the power grid sending the civilian population back to the 1800s seems like fantasy?

I think the honest answer is "I dunno." On the one hand, we don't really know if the government - any government - might have taken the risk (including Carrington Event) seriously and instituted some potentially simple upgrades to various power grids that means a pulse would just trip some circuit breakers. On the other hand, we don't *really* know for certain what the effect of a whole raft of potential EMP events would be on a vast array of consumer electronics.

In short, it's not something that we can really test for.

 

[RyanC]

It's worth noting that military field manuals for tanks etc advise when nuclear combat seems imminent:

Drive into a sheltered location (if possible) and then (if possible), turn off your tank and disconnect the radio aerial from your radio.

Then to turn on the tank and reconnect the aerial after the nuke goes off. I wonder why...

 

[RyanC]

To wit:

http://glasstone.blogspot.com/2006/03/samuel-glasstone-and-philip-j-dolan.html

The guy who runs the website sounds a bit...nutty, but he does have some good information.

USSR Test ‘184’ on 22 October 1962, ‘Operation K’ (ABM System A proof tests) 300-kt burst at 290-km altitude near Dzhezkazgan. Prompt gamma ray-produced EMP induced a current of 2,500 amps measured by spark gaps in a 570-km stretch of 500 ohm impedance overhead telephone line to Zharyq, blowing all the protective fuses. The late-time MHD-EMP was of low enough frequency to enable it to penetrate the 90 cm into the ground, overloading a shallow buried lead and steel tape-protected 1,000-km long power cable between Aqmola and Almaty, firing circuit breakers and setting the Karaganda power plant on fire.

...

The 550 km East-West telephone line was 7.5 m above the ground, with amplifiers every 60 km. All of its fuses were blown by the induced peak current, which reached 2-3 kA at 30 microseconds, as indicated by the triggering of gas discharge tubes. Amplifiers were damaged, and lightning spark gaps showed that the potential difference reached 350 kV. The 1,000 km long Aqmola-Almaty power line was a lead-shielded cable protected against mechanical damage by spiral-wound steel tape, and buried at a depth of 90 cm in ground of conductivity 10-3 S/m. It survived for 10 seconds, because the ground attenuated the high frequency field, However, it succumbed completely to the low frequency EMP at 10-90 seconds after the test, since the low frequencies penetrated through 90 cm of earth, inducing an almost direct current in the cable, that overheated and set the power supply on fire at Karaganda, destroying it. Cable circuit breakers were only activated when the current finally exceeded the design limit by 30%. This limit was designed for a brief lightning-induced pulse, not for DC lasting 10-90 seconds. By the time they finally tripped, at a 30% excess, a vast amount of DC energy had been transmitted. This overheated the transformers, which are vulnerable to short-circuit by DC.