Explosively pumped flux compression generator

EPFCGs are popular as power sources for electronic warfare devices known as transient electromagnetic devices that generate an electromagnetic pulse without the costs and side effects of a nuclear weapon, a form of cyberwar.

Characteristics

An EPFCG is a single-shot pulsed power supply; it can only be used once, and the device is destroyed in operation. An EPFCG package that could be easily carried by a person can produce pulses in the millions of amperes - tens of terawatts[?], excedding the power of a lightning strike by orders of magnitude.

They require a starting current pulse to operate, which is usually supplied from a capacitor bank which has in turn been charged from batteries or the power supply of the vehicle carrying the weapon.

Construction

The most widespread and developed design for an EPFCG is the coaxial design. This consists of a cylindrical core of high explosive surrounded by a conductive armature tube, an air gap, then a conductive winding.

In operation, the start current is supplied to the conductive winding from one end of the device, and the explosive is detonated from the same end. As the explosion propogates along the explosive core it forces the armature tube out across the air gap and into contact with the winding, forcing the magnetic flux in the air gap (induced by the start current in the winding) to be compressed against the winding, then shorting the winding out, starting from the input end of the device and progressing towards the output end as the explosion continues.

The motion of the armature tube through the intense magnetic field set up by the start current acts as a magnetic brake, resisting the explosion, and converting the explosive energy into electrical energy in the outer winding.

The far end of the winding is then tapped for power output. The output pulse will last as long as it takes the explosion to propogate all the way along the tube.

When used as an electromagnetic pulse weapon, the EPFCG's output is fed to an antenna, possibly via some wave shaping electronics capacitors and inductors. The output pulse is converted directly into a radio pulse which can damage electronics, and at short range will also kill people due to heating effects.

Other uses

EPFCGs could be used to drive pulsed lasers for military applications, and for such interesting possibilities as portable nuclear magnetic resonance analysers; the EPFCG being used to provide energy for the powerful magnetic field required, and maybe the radio pulse used to probe the sample (using a single pulse for FTNMR), thus avoiding the need for large superconducting storage magnets. They might conceivably be kept on hand at fusion power plants to supply ignition wnergy for nuclear fusion reactions.

External link

• http://www.tfd.chalmers.se/~valeri/EMP