zpinch

The z-pinch is a plasma confinement and compression technique in which a strong axial current is passed through a plasma column or a wire array. The current generates an azimuthal magnetic field around the plasma, and the resulting magnetic pressure acts inward to compress the plasma radially. This magnetic confinement is brief, occurring on nanosecond to microsecond timescales in pulsed-power devices.

Configurations of the z-pinch commonly include wire-array z-pinches, where many fine metal wires are arranged in a cylinder and a rapid current vaporizes and ionizes them; and gas-pillared or gas-fed z-pinches, where plasma is formed in a gas or low-density medium inside a coaxial chamber. In both cases, the current is directed along the axial direction (the z-axis), and the resulting magnetic forces drive an inward collapse of the plasma.

The z-pinch is noted for producing high temperatures and densities, making it a useful source of X-rays and a platform for high-energy-density physics experiments. Pulsed-power facilities, such as the Z-machine at Sandia National Laboratories, generate currents of tens of megaamperes in nanoseconds to create intense X-ray pulses used for imaging and for inertial confinement fusion research. The same principles underpin laboratory studies in radiation-dominated plasmas and dynamic hohlraums.

A major challenge for z-pinch devices is plasma instability. Sausage (m=0) and kink (m=1) instabilities can distort the plasma column and disrupt confinement, limiting performance and uniformity. Researchers investigate stability control, tailored current rise, and electrode design to mitigate these effects. Despite difficulties, the z-pinch remains a prominent concept in pulsed-power physics and high-energy-density experiments.