* Astronomy

The Z machine is the largest X-ray generator in the world and is designed to test materials in conditions of extreme temperature and pressure.
Recently a temperature of 2 to 3 billion degrees Kelvin -- hotter than the interior of any known star -- has been achieved in the lab in New Mexico.

The temperature record was set in a test shot at the Z Pinch device at Sandia National Laboratory, where an immense amount of electrical charge is stored in a device called a Marx generator. Many capacitors in parallel are charged up and then suddenly switched into a series configuration, generating a voltage of 8 million volts.

This colossal electrical discharge constitutes a current of 20 million amps passing through a cylindrical array of wires, which implodes. The imploding material reaches the record high temperature and also emits a large amount of X-ray energy.
Why the implosion process should be so hot, and why it generates X-rays so efficiently (10-15 percent of all electrical energy is turned into soft X-rays), has been a mystery.

In fusion power design, Z-pinch, or zeta pinch is a type of plasma confinement system that uses an electrical current in the plasma to generate a magnetic field that compresses it. The name refers to the direction of the earliest experimental devices in England, where the current flowed down a vertical quartz tube, the Z-axis on a normal mathematical diagram.

Now Malcolm Haines of Imperial College, in London, and his colleagues, think they have an explanation. In the hot fireball formed after the jolt of electricity passes through, they believe, the powerful magnetic field sets in motion a myriad of tiny vortices (through instabilities in the plasma), which in turn are damped out by the viscosity of the plasma, which is made of ionised atoms.
In the space of only a few nanoseconds, a great deal of magnetic energy is converted into the thermal energy of the plasma. Last but not least, the hot ions transfer much energy to the relatively cool electrons, energy which is radiated away in the form of X-rays.

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