On Tuesday, December 14, the National Spherical Torus Experiment (NSTX) at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) produced a one million ampere plasma current - a new world record for a spherical torus device. The result was accomplished nine months ahead of schedule.

Secretary of Energy Bill Richardson said, "I'm delighted that the NSTX experiment has met this technical milestone nine months ahead of schedule. We can now begin the scientific investigations that the machine is designed to do."

One million amperes is the highest plasma current ever produced in a spherical torus device. The previous record is 310,000 amperes achieved in a smaller spherical torus device called START - the Small Tight Aspect Ratio Tokamak - at the Culham Laboratory in England.

NSTX, which began operating in February 1999, is designed to test the physics principles of spherical torus plasmas. It produces a plasma that is shaped like a sphere with a hole through its center. This configuration may have several advantages, a major one being the ability to confine a higher plasma pressure for a given magnetic field strength. This could lead to a less expensive development path for fusion energy.

The production of a one-million-ampere plasma current on NSTX required the appropriate plasma shaping, such as the width and height of the cross section of the plasma torus. Proper plasma shaping helps eliminate plasma instabilities. By October of 1999, the NSTX team had produced all of the desirable plasma shapes that they plan to use on NSTX, also a key aspect of preparation for research.

NSTX is one of a new class of relatively inexpensive devices called "Proof-of-Principle" experiments, currently being used to establish the scientific underpinnings for the development of fusion energy.

NSTX Program Director Martin Peng said, "The goals of the next few years of research on NSTX are to produce high-quality scientific results and excellent plasma performance. If successful, NSTX will have an impact on the design of future devices. These future machines would extend the temperatures, densities, and other plasma parameters to the levels necessary for fusion energy production."

For further information, contact Martin Peng (mpeng@pppl.gov).