Z Pulsed Power Facility

The Z Pulsed Power Facility, informally known as the Z machine or simply Z,[1] is the largest high frequency electromagnetic wave generator in the world, operated by Sandia National Laboratories in Albuquerque, New Mexico.

In particular, it gathers data to aid in computer modeling of nuclear weapons and eventual fusion pulsed power plants.

The Z machine's origins can be traced to the Department of Energy (DoE) needing to replicate the fusion reactions of a thermonuclear bomb in a lab environment to better understand the physics involved.

The November 1978 issue of Scientific American carried Yonas' first general-public article, "Fusion power with particle beams".

In a Z-pinch, the fast discharge of current through a column of plasma causes it to be compressed towards its axis by the resulting Lorentz forces, thus heating it.

By removing the polystyrene core, Sandia was able to obtain a thin 1.5 mm plasma cord in which 10 million amperes flowed with 90 megabars of pressure.

[citation needed] The key attributes of Sandia's Z machine[11] are its 18 million amperes of current and a discharge time of less than 100 nanoseconds.

In 2001, Sandia introduced the Z-Beamlet laser (from surplus equipment of the National Ignition Facility) as a tool to better image the compressing pellet.

The Z machine was dismantled in July 2006 for this upgrade, including the installation of newly designed hardware and components and more powerful Marx generators.

[24] Sandia's roadmap for the future includes another Z machine version called ZN (Z Neutron) to test higher yields in fusion power and automation systems.

ZN is planned to give between 20 and 30 MJ of hydrogen fusion power with a shot per hour using a Russian Linear Transformer Driver (LTD) replacing the current Marx generators.

Sandia Labs recently proposed a conceptual 1 petawatt (1015 watts) LTD Z-pinch power plant, where the electric discharge would reach 70 million amperes.

Overhead view from a fisheye lens of the Z machine at Sandia National Laboratory. Due to the extremely high voltage , the power feeding equipment is submerged in concentric chambers of 2 megalitres (2,000 m³) of transformer oil and 2.3 megalitres (2,300 m³) of deionized water , which act as insulators . Nevertheless, the electromagnetic pulse when the machine is discharged causes impressive lightning, referred to as a "flashover", which can be seen around many of the metallic objects in the machine.
Z machine cross section
Z machine diagram
The stages of a typical MagLIF implosion at Z.
  1. A laser preheats the fuel.
  2. An axial current is driven through the liner.
  3. The current induces an azimuthal magnetic field.
  4. The magnetic force implodes the liner, compressing and further heating the fuel.
Proposed model of a 1 petawatt LTD-based z-pinch accelerator.
104 m diameter, 70 megaamperes, 24 megavolts.