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EMP blast - what would happen really?

D

Don Klipstein

Jan 1, 1970
0
AGAIN, LIGHT IS NOT the only thing such an event releases.

A very large MAGNETIC PULSE, which is quite capable of moving
electrons in ANY conductor it encounters as it passes by. Said motion
can be at such an excited level and rate that catastrophic damage can
occur in delicate devices.

(SNIP what an EMP can do)

If this pulse is going to travel through open air or space for many
miles, it will consist of electromagnetic radiation, which consists of
photons whether or not the electromagnetic radiation has spectral content
in the visible light range.

- Don Klipstein ([email protected])
 
J

John Woodgate

Jan 1, 1970
0
dated said:
I may be wrong but....

I have a hard time beliving that an EMP pulse at 20 miles is worse than
a lightning bolt at 100 feet. With simple design you can survive a
lighting bolt at 100 feet. Cars do it all the itme.

If the EMP pulse is closer than 20 miles, the EMP is the least of your
problems.

All you EVER wanted to know, and more, about HEMP is here, but not free:http://tinyurl.com/llun4
 
P

przemek klosowski

Jan 1, 1970
0
I have a hard time beliving that an EMP pulse at 20 miles is worse than a
lightning bolt at 100 feet. With simple design you can survive a
lighting bolt at 100 feet. Cars do it all the itme.

I saw the power spectrum of different EMP sources and the amazing thing
about the nuke-induced EMP was that the peak was at sub-Hertz. I.e., it's
a huge V/cm potential lasting a fraction of a minute.
 
J

jasen

Jan 1, 1970
0
I've heard that if an EMP weapon were used, *nothing* in the blast area
that relies on electricity would work.

Is this really true?
no.

If you had an alkaline battery, it would still put out a voltage,
correct?
yep.

Failing that, one could still take a roll of paper towels, immerse the
towels in a salt solution (table salt should do), place alternating
plates of copper and zinc (or any two dissimilar metals), and obtain a
current... right?

that too.
Would motors still work, or would their windings be guaranteed
destroyed in an EMP blast?

probably.

the main stuff that's likely to fail are semiconductors, that means
electronic devices (except old valve equipment)

Bye.
Jasen
 
R

Robert Latest

Jan 1, 1970
0
On 14 Aug 2006 15:07:56 -0700,
in Msg. said:
Although, true, it has been a matter of debate for a long time,

Not any more.
nonetheless; is light a wave or a particle?

Both. Or none. "Wave" and "particle" are just aggregations of glyphs
describing abstract concepts.
Is light considered electro-magnetic energy?

Yes.

robert
 
K

Ken Smith

Jan 1, 1970
0
When a defecting (for money) Soviet pilot landed a MiG fighter in japan
towards the end of the Cold war, and US techs stripped it down, they
laughed at how "backward" the Soviets were, still using vacuum tubes in
the 1980s. Such dinky little tubes as well. Then they stopped laughing
when they noticed a couple more features and realised they were looking
at a practically EMP proof plane.

I heard a different version of the story that ended like this:

Then someone suggested that if the soviet aircraft were so backwards, it
would be safe to cut the airforce's budget. Then they stopped laughing
and *discovered* how EMP proof the aircraft was.
 
K

Ken Smith

Jan 1, 1970
0
colin said:
I was wondering if the EMP is polarised ?
well I assume it cant be unipolar, so what would determine the polarisation,
maybe its randomly poilarised,
otherwise if you were in the right axis you wouldnt be affected.

Sheldon Breiner had a rubidium (or was it cesium) magnetometer set up at
Stanford University in California during the south pacific test. He saw a
few hundred nT of field change. It was not a step function but more like
a few cycles of a sine wave. The effects decreased with time. Initially
the decrease was rapid but once it was down to a few nT, it remained at
that sort of level for an hour or so.

He also had a magnetometer right above an underground test. That
magnetometer showed nothing measurable when the blast happened. I think
this is good evidence that the EMP effect is entirely caused by the bombs
interaction with its environment. It is not a property of the blast its
self.
 
J

John Woodgate

Jan 1, 1970
0
dated Tue said:
He also had a magnetometer right above an underground test. That
magnetometer showed nothing measurable when the blast happened. I
think this is good evidence that the EMP effect is entirely caused by
the bombs interaction with its environment. It is not a property of
the blast its self.

I have seen an explanation involving the ionised air from the detonation
short-circuiting the E-layer of the ionosphere to the surface.
 
Ken said:
I heard a different version of the story that ended like this:

Then someone suggested that if the soviet aircraft were so backwards, it
would be safe to cut the airforce's budget. Then they stopped laughing
and *discovered* how EMP proof the aircraft was.


So... does our modern fighter aircraft fleet now have this... um...
EMP-resistant "feature"?

Thanks guys,

Michael
 
M

martin griffith

Jan 1, 1970
0
I heard a different version of the story that ended like this:

Then someone suggested that if the soviet aircraft were so backwards, it
would be safe to cut the airforce's budget. Then they stopped laughing
and *discovered* how EMP proof the aircraft was.


So... does our modern fighter aircraft fleet now have this... um...
EMP-resistant "feature"?

Thanks guys,

Michael[/QUOTE]
http://en.wikipedia.org/wiki/Explosively_pumped_flux_compression_generator
and
http://en.wikipedia.org/wiki/Electromagnetic_pulse

If you follow the links there is a lot of infomation


martin
 
G

Genome

Jan 1, 1970
0
Jim Thompson said:
'Cept it doesn't happen. Think about it. Fuses on every pole.

...Jim Thompson
--

Gosh, I should be persona non gratis or whatever. Apologies for my last
rant.

Of course it'll probably happen again.

DNA
 
R

Richard Henry

Jan 1, 1970
0
So... does our modern fighter aircraft fleet now have this... um...
EMP-resistant "feature"?

Modern military equipment is normally protected against (and tested for
resistance to) EMP damage. This is usually accomplished by a
combination of shielding, I/O transient suppression, and special power
supply techniques.

The USAF used to ahve a large test rig that looked like a railroad
trestle build over a hemispherical pit that is surrounded by pulse
generating coils. It was large neough that an entire airplane can be
placed on the trestle for testing. For purity of testing (and to
reduce the likelihood of damage) no steel fasteners were used in the
construction of the trestle.
 
R

Rich Grise

Jan 1, 1970
0
I was wondering if the EMP is polarised ? well I assume it cant be
unipolar, so what would determine the polarisation, maybe its randomly
poilarised,
otherwise if you were in the right axis you wouldnt be affected.

It's probably indeterminate - the EMP is, after all, one HUGE photon,
which presents as a quantum wave front; where it collapses would depend
on what it hits, I'd think.

Cheers!
Rich
 
R

Rich Grise

Jan 1, 1970
0
Sheldon Breiner had a rubidium (or was it cesium) magnetometer set up at
Stanford University in California during the south pacific test. He saw a
few hundred nT of field change. It was not a step function but more like
a few cycles of a sine wave. The effects decreased with time. Initially
the decrease was rapid but once it was down to a few nT, it remained at
that sort of level for an hour or so.

He also had a magnetometer right above an underground test. That
magnetometer showed nothing measurable when the blast happened. I think
this is good evidence that the EMP effect is entirely caused by the bombs
interaction with its environment. It is not a property of the blast its
self.

The molten rock around the blast was probably conductive, and shorted
it out, like a Farady cage.

Thanks,
Rich
 
T

Tim Williams

Jan 1, 1970
0
So... does our modern fighter aircraft fleet now have this... um...
EMP-resistant "feature"?

My older brother, who is with the Navy, once brought home some, lesse I have
the datasheets, CK5703 and CK5744 type miniature (wire-lead, T-3 bulb)
single triodes. He said that, on the fighters (F-18ish) he was working
with, there are the normal systems, backup systems, robust backup-backup
systems, and at the very bottom, when all the hit shits the fan...a handful
of tubes so you don't completely drop out of the air.

Tim
 
T

Tim Williams

Jan 1, 1970
0
Rich Grise said:
It's probably indeterminate - the EMP is, after all, one HUGE photon,

Curious, even if it contains harmonics to 1GHz, that's a single-photon
energy of E = hf = 4.136e-15 eV-s * 1e9 s^-1 = 4.136e-6 = 4.14ueV. We're
talking colder than the universe's background radiation temperature (average
630ueV!). Did you happen to redefine Plank's constant while I was out?

Nah, there's just a few 10^12's of photons in that pulse, mmmkay.

Tim
 
K

Ken Smith

Jan 1, 1970
0
The molten rock around the blast was probably conductive, and shorted
it out, like a Farady cage.

I think you mis-spelled "rock vapor".

I don't think the time constant of that shorted turn would be long enough
to keep the low frequencies in.
 
K

Ken Smith

Jan 1, 1970
0
Rich Grise said:
It's probably indeterminate - the EMP is, after all, one HUGE photon,
which presents as a quantum wave front; where it collapses would depend
on what it hits, I'd think.

No, its the other way. An EMP is such a crowd of low energy photons that
they trip over each other as they try to spread out. Thats why the spread
rate is less than the speed of light. :)
 
M

Marc Guardiani

Jan 1, 1970
0
tlbs101 said:
Even automobiles have so much
electronic gear (computers, sensors) that they would be rendered
useless after an EMP event. This is one [small] reason I keep a 1969
Chevy truck -- no electronics.

What, no radio? :)
 
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