Public Release: 

Studying plasmas for promising X-ray fusion system

Cornell University

ITHACA, N.Y. -- Cornell University is leading a newly formed international consortium of six universities and institutes collaborating on high-energy density plasma research, with the aim of developing a promising fusion power source.

The institutions have been awarded a three-year cooperative agreement by the Department of Energy (DOE) and the National Nuclear Security Administration, a quasi-autonomous agency within the DOE, to establish the Center for the Study of Pulsed-power-driven High Energy Density Plasmas at Cornell.

The Cornell center will receive $2,000,000 annually, with about 35 percent going to the partner institutions: Imperial College, London; the University of Nevada, Reno; the University of Rochester; the Weizmann Institute of Science, Israel; and the P.N. Lebedev Physical Institute, Moscow.

The director of the Cornell center is Bruce Kusse, professor of applied and engineering physics, and the associate director is David Hammer, the J.C. Ward Professor of Nuclear Energy Engineering. Both are researchers in the Cornell Laboratory of Plasma Studies.

For the past few years, a major research direction for the laboratory has been inertial confinement fusion, in association with Sandia National Laboratories, Albuquerque, N.M. The fusion facility at Sandia, the so-called Z-Machine, recently announced the creation of the hot, dense plasma that produces neutrons associated with nuclear fusion, by passing 20 million amperes of electricity through a cylindrical array of up to 600 fine metal wires.

The wires are crushed together by the extremely high magnetic field produced by the current, and become so hot and dense that they produce an X-ray pulse of 100 trillion watts for a few billionths of a second. The X-rays are used to compress and heat hydrogen fusion fuel to near solid density at about 10 million degrees Celsius (18 million degrees Fahrenheit).

Fusion reactions similar to the ones taking place in the sun and other stars are induced by the high fuel temperatures and densities achieved by the Z-machine.

A smaller version of the Z-Machine -- operating at 1 million amperes -- is now being built at Cornell in order to allow wire array experiments to be carried out that are more relevant to those performed at Sandia.

Kusse and Hammer note that the high-energy density research to be carried out by the new Cornell center springs, in part, from the Z-Machine results and will encompass the fundamental physics as well as applications of high-energy density plasmas -- the state of matter produced when the temperature is so high that atoms break apart into ions and electrons.

Studies of high-energy density plasmas require a different set of measurement techniques from those used on lower-density, magnetically confined plasmas, Hammer says. As a result, he says,"the development of the necessary diagnostic devices is an important component of the center research portfolio." One example is the discovery by Hammer and his research group of the X-pinch point imaging source. The group has found that bursts of X-rays from the high-density plasma can produce high-resolution radiographs (X-ray photographs) of very small objects.

Other center research, says Kusse, will include "equation of state studies at extremely high pressures" and the simulation of high-energy density astrophysical phenomena, such as plasma jets. Astrophysical plasma studies will be carried out by Richard Lovelace, Cornell professor of applied and engineering physics, and the groups at the University of Rochester and Imperial College. University of Nevada researchers will develop X-ray spectroscopic diagnostic instruments that can be taken to laboratories at Cornell, Imperial College or Sandia. The researchers also will carry out detailed atomic physics calculations to help interpret X-ray spectroscopy experiments.

The Weizmann Institute team will provide expertise in atomic spectroscopy for measurements of extremely high magnetic fields. The Lebedev Institute will carry out magnetohydrodynamic computer simulations and also will initiate a line of experiments with exploding wires in high-pressure gas or in condensed matter instead of in a vacuum.

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Related World Wide Web sites: The following sites provide additional information on this news release. Some might not be part of the Cornell University community, and Cornell has no control over their content or availability.

Center for the Study of Pulsed-power-driven High Energy Density Plasmas: http://www.plasmacenter.cornell.edu/
Sandia National Laboratories: <http://www.sandia.gov/

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