Mike Luther wrote:
A friend of mine cited a claim in a brand new book, "The Lost Symbol" by
Dan Brown. So said, in it is a claim of a new weapon of choice that is
installed in some USA military helicopters which is cable of aiming an
actual EMP pulse at a target below that destroys computer and electronic
equipment of focus to the pulse! Same as a 'normal' 30Megavolt/Meter
EMP pulse from a nuclear device, or even a huge Solar Burst. As told me
they used it recently to silence an Email production site they had to
quickly do so that they couldn't do any other way, per this book....

Duhh .....

Few people seem to recall the last huge Solar Burst we got here in the
USA in the mid-1800's about the time of the Golden Spike. So history
says, it completely took out most of all the at-the-time telegraph
systems which all had to be rebuilt or replaced.

At any rate, can anyone here conjecture, or better still, teach me how
it would be possible to create and focus an EMP pulse that could be used
as described in an airborne delivery machine? What might the antenna be
like?

Just curious.

W5WQN


Gyrotron, driven by a Flux Compression Generator.

basically a very high power microwave transmitting tube at a high enough
frequency where a moderate sized antenna gives a narrow beamwidth (e.g.
at 10GHz, a 2 meter antenna has about a 1 degree beamwidth.. 100GHz with
a 20 cm antenna does the same.) , with a HV pulse generator that uses
the mechanical energy from an explosion to generate the HV high current
pulse to run the tube.


Now.. 30 MV/m at a distance of say, 200 meters..

Assuming you're in the far field, so E/H = 377 ohms.. H = 30MV/m/ 377 =
0.08 MA/m. 30MV/m * 80kA/m = 2.4E12 W/m^2... that's a pretty high power
density (far higher than you'd need, in this application by the way...
a few tens of kW/square meter would probably do)

But, continuing on.. let's say you've got a 0.57 degree beamwidth.
That's about 0.01 radian, so at 200m, the "spot" is 2 meters in
diameter, or, call it 3-4 square meters.

That means the source has to put out a peak power of about 1E13 Watts..
Say the pulse is a microsecond long.. that's 1E7 joules (10 Megajoules)
which isn't a lot of energy. But a terawatt peak power? That's hard to
believe.

So lets move on.. Average powers of a megawatt are certainly
reasonable.. Let's scale back our field to 30 kV/m (so the power density
is now 2.4E6W/m^2... still 2400 times brighter than the sun)

That's a lot more realistic, and still enough to zap stuff.