Quest to tame energy of stars revives researchers

Fusion energy could become a reality as soon as the mid 21st century Competing labs now sharing


PLAINSBORO, N.J. -- In its heyday it was a palace among physics laboratories, with an enviably fat budget, ample support staff and the prestige that comes to research institutions working at the cutting edge in solving global problems. But today, the Princeton Plasma Physics Laboratory, still a leader in hydrogen fusion research, is so short of cash that it can no longer afford even a receptionist.

However, a dry spell of discouragements and spending cuts for fusion research may be ending. With their backs to a financial wall, specialists in the field are banding together to pursue the elusive goal of harnessing thermonuclear fusion, the process that drives the sun and hydrogen bombs.

Leaders in the field say the new spirit calls for lean, selective financing of small-scale experiments as well as the large ones that have dominated the field's history, increased cooperation between long-standing competitors, and a lot of patience.

Proponents of hydrogen fusion, the joining together of hydrogen nuclei to produce useful energy, have suffered too many frustrations over the years to hope for too much too soon. Fusion energy will not come tomorrow. But it could become a reality in the mid-21st century, believers say, and slow the carbon dioxide pollution of the atmosphere by the burning of fossil fuels a problem that may be leading to disastrous global warming.

Pressed by tight budgetary constraints imposed by Congress, competing fusion laboratories have begun sharing and coordinating their research to a greater extent than ever and have drafted guidelines for allocating their limited resources as they would an investment portfolio, giving major financing to the most promising projects but gambling some funds for high-risk but potentially fruitful experiments.

First meeting

Next month fusion scientists and engineers from around the world will hold a meeting in Snowmass, Colo., to discuss all the devices and proposals currently on the table. It will be the first meeting of its kind, according to its co-chairman, Dr. Michael E. Mauel of Columbia University, and it signals a growing realization that if fusion energy is ever to become a reality it will require global cooperation rather than endless competition between nations and individual laboratories.

The main obstacle to accelerated research fusion, many scientists say, is the disincentive created by low fossil fuel prices.

"Right now," said Dr. Robert J. Goldston, director of the Princeton Plasma Physics Laboratory in New Jersey, "a bottle of table water costs more than a bottle of gasoline. But cheap oil won't last forever, and in any case, the burning of fossil fuels may be contributing to global warming. Fusion, which could produce enormous amounts of energy at reasonable cost with only negligible amounts of radioactive waste and no pollution of the atmosphere, may be our only practical alternative to fossil fuels."

No doubters

No one doubts that hydrogen fusion can be achieved. Huge pulses of fusion power have already been generated by experimental fusion reactors in the United States and Europe. The trouble is that until now, conventional generating plants have had to supply more energy to kindle a thermonuclear pulse than the pulse itself produces.

No one has yet been able to squeeze thermonuclear fuel tightly enough and long enough to ignite a self-sustaining fusion reaction.

In the sun, energy is produced when hydrogen nuclei fuse to produce helium, a heavier element. But for hydrogen nuclei to overcome their mutual electrostatic repulsion and get close enough to fuse, they must have very high velocities, that is to say, they must be very, very hot.

Scores of different reactor designs have been built, tested and abandoned over the years, most of which belong to one of two main categories: magnetic confinement, the squeezing of plasma by magnetic fields; and inertial confinement, the squeezing of hot gas by the implosion of miniature hydrogen bombs.

A magnetic confinement device uses powerful interlocked magnetic fields to contain and compress hot, electrically charged plasma (a kind of gas) within a vacuum chamber. The plasma must never touch the solid walls of its container; otherwise, it instantly loses its heat and can never be coaxed into undergoing fusion. Everything depends on keeping the plasma's magnetic bottle tightly stoppered, which is no easy task.


Most of the stars of magnetic fusion experiments have been devices called tokamaks. One of the largest and most successful of these machines was the Princeton laboratory's big Tokamak Fusion Test Reactor, which in 1994 produced a record-breaking pulse of 10.7 million watts of fusion power. It was shut down two years ago for lack of money.

The device's lineage goes back to the early 1950s, when the Soviet scientists Andrei Sakharov and Igor Tamm proposed the design and named it tokamak the Russian acronym for "toroidal magnetic chamber" a doughnut-shaped machine that compresses fusion fuel magnetically.

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