Put it on the back of a military jet and if a missile locks onto the plane, the generator can release a pulse that scrambles the missile's electronics. Marx generators have the advantage of being able to operate repeatedly. The energy stored in a kilo or two of TNT can be turned into a huge pulse of microwaves using a device called a flux compressor. This uses the energy of an explosion to cram a current and its magnetic field into an ever-smaller volume. Sending this pulse into an antenna creates a deadly burst of radiowaves and microwaves.
Simplicity is one of the flux compressor's big attractions.
Just take a metal tube, pack it with explosives, and stick a detonator in one end. Then fix the tube inside a cylinder of coiled wire, which has a wire antenna attached at the far end. Setting off the detonator triggers the charge, sending an explosion racing along the tube at almost 6000 metres per second. If you could slow this down, you'd see that in the instant before the explosive pressure wave begins to shatter the device, the blast flares out the inner metal tube. As the explosive front advances, the magnetic field is squeezed into a smaller and smaller volume.