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| TFTR
Plasma Discharge |
Plasma science (the study of ionized
gases) is critical to the development
of fusion energy (involving the fusion
of nuclei), which could be an abundant
and attractive energy source in the
future. Scientists at the Princeton
Plasma Physics Laboratory recently
discovered a new plasma confinement
regime. By decreasing the influx of
neutral gas from the walls of the
vacuum chamber containing the plasma,
they obtained peak plasma density
profiles and high ion temperatures.
This led to a reduction in energy
loss by a factor of two to three and
an increase in the number of thermonuclear
fusion reactions by a factor of about
20. Scientists later used this enhanced
confinement regime to produce 10.7
million watts of fusion power, with
a total yield of 4.2 million joules,
in a deuterium-tritium plasma. (A
deuterium-tritium fusion reaction
produces a neutron and an alpha particle
[helium-4 nucleus], while mass is
converted to energy. The neutron carries
away 80 percent of this energy, and
the rest goes to the alpha particle.
In a fusion power plant, the neutron
energy would be converted to heat
to make steam for the generation of
electricity; the alpha particle energy
is transferred to the plasma and,
when sufficient to sustain the plasma
temperature, the plasma is "ignited.")
Three scientists won the American
Physical Society Award for Excellence
in Plasma Physics Research in 1988.
Scientific Impact:
The enhanced confinement regime was
used to study the confinement of fusion-produced
alpha particles. The scientists determined
that alpha particle confinement and
loss agreed with theoretical predictions,
and they observed the first indications
of alpha particle heating of the background
plasma.
Social Impact: This
advance helped lay the groundwork
for promoting fusion as an attractive
energy source. If converted to electricity,
the 10.7 million watts of fusion power
produced in this experiment would
meet the needs of about 3,000 average-sized
homes.
Reference: "High
Temperature Plasmas in a Tokamak Fusion
Test Reactor," J. D. Strachan, M.
Bitter, A. T. Ramsey, ..., Phys.
Rev. Lett. 58, 1004 (1987).
"Fusion Plasma Experiments on TFTR:
A 20-year Retrospective," R. J. Hawryluk,
S. Batha, W. Blanchard, M. Beer, ...,
Phys. Plasmas 5, 1577 (1998).
URL:
http://www.pppl.gov/projects/pages/tftr.html
Technical Contact:
Steve Eckstrand, Research Division,
301-903-5546
Press Contact: Jeff
Sherwood, DOE Office of Public Affairs,
202-586-5806
SC-Funding Office:
Office of Fusion Energy Sciences |
