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Fusion

Fri Aug 25 2006, 08:04AM

Registered Member #354 Joined: Thu Mar 30 2006, 10:12AM
Location:
Posts: 55

I would like build a vircator that is one of the more cheap and powerful electric generator, but I do not found enought info.
I think it is like a capacitor with some C-4 (or other) explosive at the center: My idea is to build an oil capacitor but with using a metal net instead of a foil and use an explosive mixture made with potasium clorate and sugar (60/40)

Do anybody have made one?
Do anybody has more info?

Here is the vircator info I found:

The axial vircator is the simplest by design, and has generally produced the best power output in experiments. It is typically built into a cylindrical waveguide structure. Power is most often extracted by transitioning the waveguide into a conical horn structure, which functions as an antenna. AVs typically oscillate in Transverse Magnetic (TM) modes. The Transverse Vircator injects cathode current from the side of the cavity and will typically oscillate in a Transverse Electric (TE) mode.

The fundamental idea behind the Vircator is that of accelerating a high current electron beam against a mesh (or foil) anode. Many electrons will pass through the anode, forming a bubble of space charge behind the anode. Under the proper conditions, this space charge region will oscillate at microwave frequencies. If the space charge region is placed into a resonant cavity which is appropriately tuned, very high peak powers may be achieved. Conventional microwave engineering techniques may then be used to extract microwave power from the resonant cavity. Because the frequency of oscillation is dependent upon the electron beam parameters, Vircators may be tuned or chirped in frequency, where the microwave cavity will support appropriate modes. Power levels achieved in Vircator experiments range from 170 kilowatts to 40 gigawatts over frequencies spanning the decimetric and centimetric bands (ones to tens of gigahertz).

In order to obtain 4.5GHz I would use a mesh of 3.3cm cell wide

Coronafix

Fri Aug 25 2006, 08:35AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

First, as far as I can see from a quick google search, this things only use is as a weapon of extreme power.
Is this the purpose?

If not, then what else can it be used for?
Second, where does the explosive material come into the equation?
I didn't find any mention of C4 being part of the schematic!!!??!
Puzzled as to the purpose.

Bjørn

Fri Aug 25 2006, 08:58AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

The explosives supplies the energy to generate an extremely powerful pulse of current. It is not like a capacitor, but like an inductor. The archives should have some information about EMP generators and Google has a lot.

Don't play with explosives or microwaves until you have understood everything about the device.

Fusion

Fri Aug 25 2006, 09:08AM

Registered Member #354 Joined: Thu Mar 30 2006, 10:12AM
Location:
Posts: 55

Goldsphere wrote ...

First, as far as I can see from a quick google search, this things only use is as a weapon of extreme power.
Is this the purpose?

[MODEDIT: ************************************************** ****************************] If you see, the mentioned weapont produces a powerful RF in a cheap way for amateurs (extreme power became if using kgs of C-4 but not wit a few grams).
The explosive come into the equation as input power (you can convert megatons to megajoule) I would use C4 because I know its output power compared with TNT and because its power density is great.
Also some power will enter as capacitor discharge in order to produce electrons at dielctric layers that will be thrown throught capacitor conductive layers in order to create output RF power.

ragnar

Fri Aug 25 2006, 09:42AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
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Posts: 1425

There are contraptions that involve progressively short-circuiting turns of a big inductor (with a pulsed current running through it) by detonating an explosive within to wipe a conductive layer/sheet against the inside of the coil - a flux compression generator. Is this related?

[Edit: Off topic comments removed by a real moderator]

Coronafix

Fri Aug 25 2006, 10:05AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Apologies Fusion, I meant no offense, but I don't understand the practical application of such a device.
What could such a large RF energy be used for?

[Edit: Off topic comment about the off topic comments removed]

Steve Conner

Fri Aug 25 2006, 11:11AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

The vircator (VIRtual CAThode oscillatOR, IIRC) is a microwave tube that you can drive from any source of HV pulsed power. A Marx generator would be a much safer power source for lab testing.

I think the original poster is getting his EM weapons mixed up. He seems to be thinking of the American EMP bomb design that uses a vircator powered by an explosive flux compression generator. The FCG produces a high voltage pulse that is turned into a burst of microwaves by the vircator. For attacking different targets, you can unbolt the vircator stage and replace it with a set of long wire antennas that are ejected from the bomb just before it goes off, and radiate the pulse from the FCG stage directly.

I don't think an explosive FCG is a terribly safe or easy hobby project >_< It needs precision high explosive charges with precisely timed electric detonators to slam the conductors into each other in a controlled fashion, within a few microseconds of discharging a Marx generator through them to provide the initial flux that you're going to compress. Just blowing up a bunch of coils with weedkiller and sugar probably won't do jack sh*t.

The vircator isn't so dangerous, but being a vacuum tube it needs vacuum skills and equipment to build. And no, they won't let you take the parts in your carry-on baggage.

Fusion

Fri Aug 25 2006, 04:24PM

Registered Member #354 Joined: Thu Mar 30 2006, 10:12AM
Location:
Posts: 55

Explosive Magnetic flux compressos are not vircator.
I would like use a vircator to heat plasma. But my intention is make little devices in order to achieve maximum efficiency. I have read that actual vircator has a 5% efficiency.

When I made rockets I used about 100gr of cloratite ones (I do not recommend because it is better ammonia nitrate+Al+glue for that purpose) then I think it is safe for me burning 100gr cloratite vircators remotely, but I think it is not safe for scopes, PCs or other instruments!

Steve Conner

Fri Aug 25 2006, 04:43PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

A vircator doesn't have any explosives in it. It's a microwave vacuum tube like a magnetron. One kind of EMP bomb (which I'm guessing is what you want to build, like every other 14 year old kid who signs up here...) is made out of an explosive FCG driving a vircator. It probably took a lot of computer modelling and U.S. Department Of Defense money to get that to work.

Michael W.

Fri Aug 25 2006, 05:30PM

Registered Member #50 Joined: Thu Feb 09 2006, 04:07AM
Location: Vernon, B.C, Canada
Posts: 324

This explains the Vircator quite well...

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