🚀 go-pugleaf

w_tom <w_tom1@usa.net> wrote in message news:3B0D8903.2486233E@usa.net...
>    How many have seen EMP?  How many nuclear blasts have you encountered
lately?

    I have "seen" EMP a few times- it was my job to test the effects of
nuclear EMP on the Pershing II.  We had an EMP generator.  I can say
factually that EMP is real and not that hard to generate.  You do not need
nuclear weapons to do it.
    EMP is a generic term (acronym for electromagnetic pulse) and many
devices can cause it.  I later built devices specifically meant to
demonstrate this phenomenon at different levels.  You can do it on a fairly
small scale with some high voltage capacitors and a rapid discharge with
some real damage.  I mean permanent destruction of semiconductors.
    Just such a device would be a lightning gun (a type of Marx generator).
Even a large Van DeGraaf will do it.  There are companies developing small
mobile devices that will EMP a vehicle and stop it in high speed pursuits.
It uses a set of high voltage capacitors rapidly discharged against the
frame of the vehicle, and it often permanently destroys the on board
processor in the car.
    Now, back to brass tacks- a radio transmitter can indeed destroy
semiconductors with fairly low output power.  It is usually caused by
lengths of wire or other conductors that are attached to the semiconductor
in question.  These lengths can act as antennas that induce large voltages
in the junctions.  It is sen many times, but is often a difficult to
duplicate effect.  Still, this does not mean that it does not exist.

> What are the numbers associated with such fields?

    A typical nuclear EMP is on the order of a trillion watts for a few
picoseconds to a few nanoseconds.  It depends on the medium that it
encounters.  The first well known (and publically known) was the Hawaii
effects observed when a hydrogen bomb was detonated not far from the island.
There are roughly 50 exotic effects from such explosions, and EMP is only
one of them.
    High energy neutrons collide with the air molecules and lose a great
deal of energy from their momentum.  The result is electrons snapping back
into their orbitals all at once in a large region, creating a nearly
spherical plasma shell that acts as a radiating antenna.  The pulse is brief
but like a hammerblow compared to a pillow falling.
    Normal damage effects from EMP are from the high voltage field it
momentarily creates.  Numbers from 50 to 150 kilovolts per meter are common.
Testing is often done at a few hundred volts per meter.  Even though this is
"just a test", it can still destroy equipment very easily.  We had to use
all fiber optic lines to prevent losing our equipment.  I have lost too much
to transient effects in the course of my work already.  One was a rather
beefy power supply.

> The many examples are operations
> interrupted (ie computer crashes) because a very strong signal was able to
create a
> minute voltage - a temporary interruption and no where near required for
> semiconductor damage.

    Yes, that is what you are most likely to observe, but not a permanent
condition.  That is simple interference.  But under just the right (or
wrong) conditions, it can indeed destroy components.  Calculate the field
density of a transmitter at a given power and antenna configuration- you
will often see 3-5 volts per meter near the antenna.  This is for small
transmitters.
    What is this field?  Photons moving synchronously.  They are being
emitted as waves that cause electrons to oscillate rapidly in synch.  This
is the cause of a small voltage in the antenna that is then amplified in
your receiver.  But any conductive object can "see" an induced voltage due
to these synchronous electron motions.
    I don't know what you do for a living, but you certainly aren't a radio
transmitter technician because you would see that induced voltage spikes of
just a few volts can easily be made at some distance from a radio
transmitter.  To say that this just isn't going to happen is to not know the
facts.  There are now EMP weapons and while they remain fairly unreliable in
many uses, they are still viable for warfare.
    Yes, a layer of aluminum foil can usually be an effective shield to much
EMP, but when you also have cables running out of the box, you haven't
really shielded after all.  The antennas, data cables, power lines, and any
other long conductor will act as the conduit for the damaging signal, and
they are politely provided entrance right through any fancy metal case.
    Just something to get you thinking about it.

Cheers!

Chip Shults

SPAM free Email - aichip@gdi.udu.net but remove the .baryon