Faraday Cages & EMP

[turkster]

Was just reading some stuff about electronic warfare the other day and the potential effects of EMP (electromagnetic pulse) devices on electronic systems.
The worrying thing is that an explosively pumped FCG (flux compression generator) can be made very easily with easily available materials and a little research. These devices can be quite compact and extremely powerful producing tens of Terawatts of electro magnetic radiation. Hence they are almost perfect terrorist weapons.

In todays technological western world they effects of even a relativly modest EPFCG could be disastrous. It would basically wipe out all electronic, and specifically MOS, devices in the surrounding area and induce massive power spikes in power and communications cables which could propagate further afield. When you theink of the amount of electronic devices that we rely on today such an attack could bring society to a standstill.

The best way to protect or harden electronic devices to this kind of a attack is to build a Faraday cage around it. A normal computers case is basically a Faraday cage but with all the cabling going into the back it would stand no hope against and EMP bomb. Surge protectors and UPS would provide some protection from power and phoneline spikes but induced voltages would build up in the connected peripherals and wiring which would almost certainly destroy the computer. The kind of voltages neccesary to kill most CMOS devices are only c10v over voltage yet a typical FCG has the potential to induce of 1000s of volts in electronic equipment. Hence the potential effect of an FCG could be more serious over a much larger distance for computers than less delicate electronic equipment.

I dont know if much could be done to harden our computers to even the long range effects of an EMP bomb but i was wondering was anyone thinking of this?
Those with basement dens full of computers could build a Faraday cage inside their rooms and isolate all wiring going into the room with optical and mechanical decouplers etc

[Korky]

interesting...., if Bush breaks my computer with one of them, I'll be at his doorstep.

[Swafe]

i thought the elecro pulse just wiped hard drives etc?

well, mines all backed up anyway....

[turkster]

i thought the elecro pulse just wiped hard drives etc?

Well no. In fact the last thing an EMP is likely to do is actually wipe your disks, it woud destroy the controller long before that.

The thing is that the CMOS devices that computers are constructed of are extremely sensitive to overvoltage. Think of overclocking if you need to change voltage you use small increments if you put it up more than 3 volts you'd almost certainly burn out your CPU etc. The problem is that even at long range a modest EMP device could induce voltages well in excess of 3volts completly writing off nearly every component in your computer.

In the aftermath of a hypothetical EMP attack computer parts would probably become extremely hard to source as so many people would also need to replace their computers and all stock within range would have been destroyed.

If you think of it from this point of view it makes sense to think of ways to try and harden PCs from the long range effects of an EMP.
The problem is it would be quite complicated from a practical point of view.
The ideal would be a room surrounded by a Faraday cage with all communications optically coupled throught the cage and power through some kind of insulated mechanical coupler or a generator. Clearly this is beyond most of us but there must be a more practical method.

Anyone got any ideas

[blockers]

Does this still affect stuff if it is not plugged into an electric source?

[turkster]

Yeah thats the whole problem it is intenses EM radiation which induces high voltages in any conductors. Hence any susceptable electrical equipment within range would be destroyed whether it was in use, plugged in or lying on your shelf. This would include most modern cars planes services trains etc That is what makes them so dangerous.

[ed^chigliak]

Am I correct in thinking that an electric current is induced in any & every metal object in the path of the magnetic pulse. Not much of a problem for my kitchen utensils but a major problem for my computer which is sensitive to electrical fluctuations. Anyway no mater but that's how I imagine.

OK here is my solution. Beef up the case to block EMP's so you make every PC case a Faraday cage. Wire all your peripheral devices through a single hub containing RCCD like mechanical/physical breakers. The hub is optically wired to EMP detectors on the outside of the building. When an EMP pulse is detected a signal travels at the speed of light and trips the breakers thus isolating the computer. The PC has an inbuilt UPS to deal with the sudden disconnection and is reconnected after the pulse has passed. You miss a keyboard stroke or two and the mouse freezes for a split second or two. Don't know if that makes sense or is possible.

Another idea involves the use of a fuel cell to power the PC from inside a Faraday cage case. Since a fuel cell is an electrochemical energy conversion device that converts hydrogen and oxygen into water, producing electricity. Your computer is plumbed for power with plastic piping to supply hydrogen and oxygen. All peripheral devices are optical and if requiring power contain fuel cells. I like this idea better but don't know if possible either.

[Merlin]

I'm no physicist but you're ideas seem to make sense. What are the implications of having a fuel cell inside a PC though? Are the H and O delivered in liquid or gaseous form?

[Blub2k]

Lads what's the point unless the hexus servers are inside a Faraday cage you wont get on the boards anyway

[Merlin]

Then for the sake of our sanity we must put them in one!

[turkster]

Lads what's the point unless the hexus servers are inside a Faraday cage you wont get on the boards anyway

Well at least it would save you computer so that when the Hexus servers were restarted you could actually browse them with something (assuming you local telephone services had been repaired )

Am I correct in thinking that an electric current is induced in any & every metal object in the path of the magnetic pulse. Not much of a problem for my kitchen utensils but a major problem for my computer which is sensitive to electrical fluctuations. Anyway no mater but that's how I imagine.

Yeah thats the problem.

OK here is my solution. Beef up the case to block EMP's so you make every PC case a Faraday cage. Wire all your peripheral devices through a single hub containing RCCD like mechanical/physical breakers. The hub is optically wired to EMP detectors on the outside of the building. When an EMP pulse is detected a signal travels at the speed of light and trips the breakers thus isolating the computer. The PC has an inbuilt UPS to deal with the sudden disconnection and is reconnected after the pulse has passed. You miss a keyboard stroke or two and the mouse freezes for a split second or two. Don't know if that makes sense or is possible.

Another idea involves the use of a fuel cell to power the PC from inside a Faraday cage case. Since a fuel cell is an electrochemical energy conversion device that converts hydrogen and oxygen into water, producing electricity. Your computer is plumbed for power with plastic piping to supply hydrogen and oxygen. All peripheral devices are optical and if requiring power contain fuel cells. I like this idea better but don't know if possible either.

Yeah good idea. Would be possible too. The peripereal hub would actually have to be mounted on the Faraday cage so that no conducting wires passed from outside to inside the cage after the device had been tripped. This is actually similar to the system used in the Cheyenne mountain complex in the states (the base you see in Stargate it actually does exist!). They have sensors which isolate everything in the event of an EMP or nuclear device and as the buildings are actually built underground suspended on springs and made of a conducting metal the whole complex acts as a Faraday cage.
The fuel cell powered idea would definatly be more secure but much more complex to build.

[ed^chigliak]

If a big EMP device is 'detonated' will anyone be killed? Is there much to see and hear or is it just a magnetic effect? How does the human body hold up when pulsed?

[Korky]

EMP doesnt harm the human body directly, people are killed by current not voltage, the current in a EMP device is minimal.

[turkster]

Apparently a high power EMP will kill at very close range due to the heating effect of the radiation. I dont know how powerful it would need to be to do that but these things are pretty powerful

The effect is characterised by the production of a very short (hundreds of nanoseconds) but intense electromagnetic pulse, which propagates away from its source with ever diminishing intensity, governed by the theory of electromagnetism. The ElectroMagnetic Pulse is in effect an electromagnetic shock wave.

This pulse of energy produces a powerful electromagnetic field, particularly within the vicinity of the weapon burst. The field can be sufficiently strong to produce short lived transient voltages of thousands of Volts (ie kiloVolts) on exposed electrical conductors, such as wires, or conductive tracks on printed circuit boards, where exposed.

With peak power levels of the order of TeraWatts to tens of TeraWatts the current produced by a large FCG is between ten to a thousand times greater than that produced by a typical lightning stroke with ramp times of tens to hundreds of microseconds, specific to the characteristics of the device, for peak currents of tens of MegaAmperes and peak energies of tens of MegaJoules.

[malfunction]

Apparently a high power EMP will kill at very close range due to the heating effect of the radiation. I dont know how powerful it would need to be to do that but these things are pretty powerful

It works in Jedi Academy

(runs away and hides)

[Kumagoro]

well if it was at 2.54 or something GHz then you will be microwaved as in the oven that is. That particular freq is what water resonates at which is why things get hot.

You can actually make a HERF gun, High Energy Radio Freqency. in the crudest way
poss get a microwave and take the window off and the metal mesh. The mesh holes
are actually that size to stop that wavelength from escaping. So you can use that
mesh to cover your eyes ans still look. uwaves can easily **** up your vision very quickly. Also if your very brave you can take the magnatron out and put a horn
antenna on it and make it more directional. I have seen one working with a normal
microwave converted and see it take out the camera that was recording it. They
have a pretty good range apparently too.... I though about building one once as my nextdoor neighbours were pikey buggers who played music as loud as they could all day and night. But I thought it was a bit dangerous to my own electrical stuff.. so
just moved instead. I wish i had though it would have been the funking bollocks