DIII-D ACHIEVES NEW HIGH DENSITY RESULTS

Researchers at General Atomics in San Diego, using the DIII-D tokamak facility, have produced plasmas with densities above the commonly accepted limit, using a novel method of pumping hydrogen gas from the boundary of the plasma. According to GA scientist Tom Simonen, "The importance of this discovery is that, at constant plasma temperature, the fusion power increases four-fold with a doubling of the plasma density. Thus a future fusion power plant could generate more electricity, or could be made smaller."

An exceptional feature of this new result is that the plasma energy confinement did not deteriorate at high density as in previous worldwide experiments. Another important feature of the new high-density results is the manner in which heat escapes from the plasma. In previous lower-density experiments, the heat escaped in brief high power pulses, which could erode the plasma vessel walls. In the recent experiments, the heat escape pulses were five times lower in power and escaped in a more continuous fashion.

The researchers are continuing these experiments using improvements to the plasma vessel, in which a dual pump was installed to increase control of the hydrogen gas.

For further information, contact Tom Simonen (tom.simonen@gat.com) and visit the GA web site (http://fusion.gat.com)