Where Chemistry & EMP Combine

Although I'm quite a noob when it comes to electricity, I wonder how you could synchronize the initial pulse of the start current with the shortcircuiting of the armature and coil reliably? Or am I completely missing the point here?

I'm afraid you lost me at the point of the 1/4 of a cycle I was wondering though what would happen if the initial start current would be supplied by another EPFCG. If I understand it right, the total poweroutput depends on the number of coil turns and the initial current. But even with a large number of windings this would mean that you would still need an incredibly large initial pulse, wouldn't it?

There is even an entree for the "Explosively pumped flux compression generator" in wikipedia. And even better, it links to a Los Alamos paper describing the theory behind the device in detail. I wonder if it was someone from here or roguesci that made that entree available...

-->http://en.wikipedia.org/wiki/Explosively_pumped_flux_compression_generator

Supposedly, An EPFCG package that could be easily carried by a person can produce pulses in the millions of amperes and tens of terawatts, exceeding the power of a lightning strike by orders of magnitude. Saw some rumours on the net that american military may have used an EPFCG device to disrupt the main televison station in Irac, dunno if it's true though...

[Edited on 20-12-2006 by nitro-genes]

have some pics here to give you all some idea what an Explosively pumped flux compression generator looks like.

Hollow tube generators
In the spring of 1952, R.Z. Lyudaev, E.A. Feoktistova, G.A. Tsyrkov, and A.A. Chvileva undertook the first experiment with this type of generator, with the goal of obtaining a very high magnetic field.

The MK-1 generator functions as follows :

A longitudinal magnetic field is produced inside a hollow metallic conductor, by discharging a bank of capacitors into the solenoid that surrounds the cylinder. To ensure a rapid penetration of the field in the cylinder, there is a slot in the cylinder, which closes rapidly as the cylinder deforms;
The explosive charge placed around the tube is detonated in a manner that ensures that the compression of the cylinder commences when the current through the solenoid is at its maximum;
The convergent cylindrical shock wave unleashed by the explosion produces a rapid contraction (greater than 1 km/s) of the central cylinder, compressing the magnetic field, and creating an inductive current, as per the explanation above (the speed of contraction permits, to first approximation, the neglect of Joule losses and the consideration of the cylinder as a perfect conductor).

Helical generators
Helical generators were principally conceived to deliver an intense current to a load situated at a safe distance. They are frequently used as the first stage of a multi-stage generator, with the exit current used to generate a very intense magnetic field in a second generator.

The MK-2 generators function as follows:

A longitudinal magnetic field is produced in between a metallic conductor and a surrounding solenoid, by discharging a battery of capacitors into the solenoid;
After the charge is ignited, a detonation wave propagates in the explosive charge placed in the interior of the central metallic tube (from left to right on the figure);
Under the effect of the pressure of the detonation wave, the tube deforms and becomes a cone which contacts the helically wrapped coil, diminishing the number of turns not short-circuited, compressing the magnetic field and creating an inductive current;
At the point of maximal flux compression, the load switch is opened, which then delivers the maximal current to the load.
The MK-2 generator is particularly interesting for the production of intense currents, up to 108 A (100 MA), as well as a very high energy magnetic field, as up to 20 % of the explosive energy can be converted to magnetic energy, and the field strength can attain 2 × 106 gauss (200 T).

The practical realization of high performance MK-2 systems required the pursuit of fundamental studies by a large team of researchers; this was effectively achieved by 1956, following the production of the first MK-2 generator in 1952, and the achievement of currents over 100 megaamperes from 1953.

Disc generators
A DEMG generator functions as follows:

Conductive metallic discs, assembled in facing pairs to create hollow modules having the form of a lined torus, with explosive packed between pairs of modules, are stacked inside a cylinder;[4] the number of modules can vary according to the desired power (the figure shows a device of 15 modules), as well as the radius of the discs (of the order of 20 to 40 cm).
Current runs through the device, supplied by an MK-2 generator, and an intense magnetic field is created inside each module.
When initiated, the explosion begins on the axis and propagates radially outwards, deforming the disc shaped protuberances with triangular section and pushing them away from the axis. The outward movement of this section of conductor plays the role of a piston.
As the explosion proceeds, the magnetic field is compressed in the inside of each module by the conductive piston and the simultaneous drawing together of the inner faces, also creating an inductive current.
As the induced current attains its maximum, the fuse opening switch fuses and the load switch simultaneously closes, allowing the current to be delivered to the load (the mechanism for the operation of the load switch is not explained in available documentation).
Systems using up to 25 modules have been developed at VNIIEF. Output of 100 MJ at 256 MA have been produced by a generator a metre in diameter composed of 3 modules.

Here are the images:

Mk 1 generator


MK-2 generator


Disc generator





[Edited on 26-1-2008 by tito-o-mac]

[Edited on 26-1-2008 by tito-o-mac]