



Based at Sandia National Laboratories in New Mexico, it is used to research thermonuclear reactions - for example, what happens at the heart of a hydrogen bomb detonation. Now it has a more productive application: finding a way to fuse heavy water atoms to create fusion power. Fusion is the Holy Grail of the power industry: cheap, clean, safe and unlimited. The downside is, with current technology, the reaction is difficult to control.

When the machine fires, 36 cables - each as thick as a horse's torso - spark simultaneously. The cables fire a pulse of 50 trillion watts into a target the size of a cotton reel. Inside the target is a can filled with wires finer than a human hair. The wires vaporise, creating temperatures as high as 3.5 billion degrees C, the highest ever created by man and an X-ray pulse in excess of 290 terawatts.







The central vacuum chamber of the Z Machine, above, is 10ft in diameter and 20ft deep, surrounded by banks of capacitors - the enormous 'batteries' used to store the charge that fire the machine.

When the wires that are inside the tiny 'target' are vaporised, the tungsten threads are forced to travel inwards at a speed of over 3,000 miles per second, and the result is that enormous sudden release of energy.

The powerful fluctuation in the magnetic field when the machine is discharged generates an electric current in all the metallic objects in the chamber - hence the impressive lightning or 'arcs and sparks' seen here.

The 36 cables feeding the energy pulse into the Z Machine are insulated by chambers containing two million litres of insulating oil and two million litres of deionised water.