The Z Machine is a gigantic machine used to generate x-rays and extreme temperatures for the testing of hypotheses about nuclear explosions. Using tremendous power feeding apparatus, it runs a current through a tungsten or steel wire, causing it to vaporize into a charged plasma. At the same time, the tremendous current density in the surrounding air creates a magnetic field which causes the charged plasma to be further condensed, a process known as z-pinch, after the vertical axis along which the plasma was compressed in the earliest British machines. The imploding plasma produces temperatures as great as 3.7 billion Kelvin, or 3.6 billion degrees F, and generates an x-ray pulse that can induce a shock wave in a target object.
The temperatures and pressures generated in the Z Machine are so immense that the properties of nuclear fusion can be studied using them. In fact, the peak temperature is about 300 times higher than that in the core of the Sun, where nuclear fusion takes place. The power the Z Machine can achieve is so immense, that beyond achieving the "typical" fusion of deuterium and tritium (one of the lower-temperature forms of fusion), the Z Machine can fuse together light nuclei such as hydrogen or lithium atoms, which could theoretically lead to aneutronic fusion. If aneutronic fusion could be developed into a practical power generator, it would avoid many of the biohazard and handling risks associated with fusion where the energy primarily comes from ballistic neutrons, as in deuterium-tritium fusion.
Originally designed to supply 50 terawatts of power (enough to power 50 million homes) for a burst less than 100 nanoseconds, the Z Machine was redesigned to supply 290 terawatts of power. The electric discharge created at the instant of the A-pinch is so massive that sparks jump off every metallic object in the room where the Z Machine is located. The effect produced photos that represent some of the most memorable science photography of 2005. The electric discharge still occurs despite the power feeding equipment being submerged in 2,000 cubic meters of transformer oil and an additional 2,300 cubic meters of deionized water. The discharge is known as "arcs and sparks" or just "lightning."