Billion Degree Breakthrough at Texas A&M
In May of 2001, Experiments at Texas A&M University confirmed predictions from Lerner theory that energies above 100 keV (equivalent to 1.1 billion degrees) can be achieved with the plasma focus. This was a big step taken towards environmentally safe, cheap, and unlimited energy.
A team of researchers announced the achievement for the first time of temperatures above one billion degrees in a dense plasma. The breakthrough, achieved with a compact and inexpensive device called the plasma focus, is a step toward controlled fusion energy using advanced fuels that generate no radioactivity. “We have achieved a key condition needed to burn hydrogen-boron fuel,” said Eric J. Lerner of Lawrenceville Plasma Physics, one of the researchers. “This fuel produces no radioactivity and can potentially generate electric energy without expensive steam generators and turbines.”
This new technology uses an approach to achieving fusion power which is qualitatively different from other current approaches and which holds the promise of providing an environmentally safe, cheap, and effectively unlimited energy source.
In recently completed test experiments, the researchers were able to achieve temperatures that reached up to two billion degrees in some shots of the plasma focus device, well surpassing previous records of 520 million degrees achieved by the commonly used tokamak device. The much larger and more expensive tokamak has been cornerstone of the US fusion program for 25 years.
In addition, the “density-confinement time product,” which is the plasma density multiplied by the duration of the plasma event, exceeded that produced in a Tokamak by a factor of eight. The larger the density and confinement time, the more fusion fuel is burned, and the greater the total energy output. The deuterium fuel used in the recent test and the hydrogen-boron fuel for planned tests, which is expected to produce a superior outcome, are both commonly available.
Mr. Lerner announced the achievement at the International Conference on Plasma Science, a major scientific conference, in Banff, Alberta, Canada . The other leaders of the research team are Dr. Bruce Freeman of Texas A and M University (College Station, Texas), where the experiments were performed last August, and Dr. Hank Oona of the Los Alamos National Laboratory (Los Alamos, NM). The results have been submitted for publication to Physica Scripta, a widely-known physics journal. The technical paper is available at: http://arXiv.org/abs/physics/0205026 .
These results are significant because temperatures above 1 billion degrees are needed to burn hydrogen-boron fuel. When hydrogen and boron fuse in a plasma focus they release energy in the form of a beam of charged particles—nuclei of helium atoms. This beam can be converted directly to electricity through a kind of high-tech transformer. This would be much cheaper than producing steam to drive turbines as occurs in fossil fuel and nuclear-electric generator plants.
Another advantage of the hydrogen boron reaction is that it produces no high-energy neutrons (in fact produces almost no neutrons at all), and so does not create radioactive products in the reactor structure or elsewhere. In contrast, deuterium-tritium, the fuel planned to be used in the tokamak and other fusion reactor concepts, releases its energy in the form of high energy neutrons, creating radioactivity in the reactors and necessitating the same steam cycle that is in use today.
In addition, the plasma focus device is much smaller and cheaper to build than the tokamak. A tokamak fills a gymnasium-sized room and costs several hundred million dollars to build. In contrast, the Texas A&M plasma focus device is contained in a converted service station and such devices cost less than $500,000 to build.
The plasma focus functions in a fundamentally different way from other fusion devices. Tokamaks and most other fusion devices use powerful magnets to attempt to stabilize the plasma - the extremely hot, electrically conducting gas in which the fusion reactions occur. This task has been likened to lifting gelatin with rubber bands.
In contrast, the plasma focus takes advantage of the natural instabilities of the plasma, so that the plasma’s own magnetic fields compress it and heat it. “The plasma focus works with the plasma, not against it,” says Lerner.
The researchers expect that their findings will be controversial. “Unfortunately, the whole fusion field is still centered on tokamak research, and most researchers simply are not willing to look at other devices, especially those as radically different as the plasma focus,” Lerner explains. As a result of this bias in the field, funding for the plasma focus has been extremely small. “I think the problem arises when funding is restricted and then scientists start to view each other as competing for funds,” Lerner says. “I don’t think that any of us should view each other as competitors for resources. I strongly feel that all alternative routes to fusion should be adequately funded. The fusion field as a whole needs more money.”
The Texas experiment was funded by NASA’s Jet Propulsion Laboratory because of the possible use of the plasma focus in space propulsion.
To help fund further research, Mr. Lerner and some colleagues have recently set up the Focus Fusion Society, which intends to raise money from the general public for plasma focus research.