Dr. TRIVELPIECE. On the viewgraph, what I have tried to show here is a quantity which is called the quality of confinement. This reflects the fact that there are so many of these light nuclei per unit volume, characterized by N, and that you need to contain them together for a certain period of time so that as they are burning they release more energy than you had to invest getting them together.

This quality parameter used by the scientists in the field is displayed as a function of time. As you can see, the progress has been very systematic and steady. There have not been any dramatic breakthroughs in this program, at least not by terms that I would use. Nevertheless, the program has proceeded to the point where the distance required to achieve the kinds of conditions that will demonstrate reactor-like plasmas is now very close and we have facilities which have been built and which are being built that will seek to achieve that.

We'll show you two of these. [Viewgraph.]

TOKAMAK FUSION TEST REACTOR

Dr. TRIVELPIECE. The first one is the Tokamak Fusion Test Reactor. In this particular case the illustration here shows the plasma which is the toroidal plasma contained by the magnetic field generated by that collection of coils which you can see around the outside. This has been under construction for some years and we have another viewgraph here which will show you its present status. [Viewgraph.]