How to make a star on Earth

Tagged: Earth, laser, Power, Technology
Source: CNN - Read the full article
Posted: 4 years 30 weeks ago

Livermore, California (CNN) -- Scientists at a government lab here are trying to use the world's largest laser -- it's the size of three football fields -- to set off a nuclear reaction so intense that it will make a star bloom on the surface of the Earth.

The Lawrence Livermore National Laboratory's formula for cooking up a sun on the ground may sound like it's stolen from the plot of an "Austin Powers" movie. But it's no Hollywood fantasy: The ambitious experiment will be tried for real, and for the first time, late this summer.

If they're successful, the scientists hope to solve the global energy crisis by harnessing the energy generated by the mini-star.

The lab's venture has doubters, to be sure. Nuclear fusion, the type of high-energy reaction the California researchers hope to produce, has been a scientific pipe dream for at least a half-century. It's been pitched as a miracle power source. But it hasn't yielded many results.

To make matters worse, the U.S. Government Accountability Office this month released an audit of the lab's work that cites delays and mismanagement as reasons it's unlikely the scientists will create a fusion reaction this year.

But researchers in Livermore, about an hour's drive east of San Francisco, say it's not a matter of if but when their laser-saves-the-Earth experiment will be proved successful.

"We have a very high confidence that we will be able to ignite the target within the next two years," thus proving that controlled fusion is possible, said Bruno Van Wonterghem, a manager of the project, which is called the National Ignition Facility.

That would put the lab a step closer to "our big dream," he said, which is "to solve the energy problems of the world."

How to build a star

Here is the boiled-down recipe for how the Livermore lab plans to cook up a star:

Step one: Build the largest laser in the world, preferably inside a drab-looking office building. (To do this, you'll have to suspend all previous notions about what a laser looks like. This one is basically a giant factory full of tubes. The laser beam, which is concentrated light, bounces back and forth over the distance of a mile, charging up as it goes.)

Step two: Split this humongous laser into 192 beams. Aim all of them -- firing-range style -- at a single point that's about the size of a BB.

Step three: On that tiny target, apply a smidge of deuterium and tritium, two reactive isotopes of hydrogen that can be extracted from seawater. Surround those atoms with a gold capsule that's smaller than a thimble.

Step four: Fire the laser!

If all goes well, the resulting reaction will be hotter than the center of the sun (more than 100 million degrees Celsius) and will exert more pressure than 100 billion atmospheres. This will smash the hydrogen isotopes together with so much force and heat that their nuclei will fuse, sending off energy and neutrons.

Voila. An itty-bitty star is born.

Miracle cure?

The fusion reaction at the heart of this recipe is the same one that fuels the sun in our solar system and other stars.

"It's the most fundamental energy source in nature," Van Wonterghem said.

Workers at the Livermore Lab insist that the reaction isn't dangerous. Their version of fusion is controlled, rather than explosive like in America's current arsenal of nuclear weapons, which include a fusion reaction.

"There's no danger to the public," said Lynda Seaver, spokeswoman for the project.

"The [worst possible] mishap is, it doesn't work."

The fusion reaction does emit radioactive neutrons. But to stop those neutrons from escaping, the Livermore lab surrounds the reaction chamber with concrete walls that are more than 6½ feet thick.

Despite the fact that the reaction will "even exceed the conditions at the center of the sun," Van Wonterghem said, the controlled fusion is expected to be incredibly small and short-lived.

The star being cooked up in Livermore this summer is expected to die 200 trillionths of a second after it's ignited, Van Wonterghem said.

And it will measure only 5 microns across, which is several times smaller than the width of a human hair.

Road to commercialization

The value of this summer's experiment in laser-induced fusion will be in proving that powerful beams of light can produce a controlled fusion reaction, Seaver said.

It will take at least another 20 years, with adequate funding, to develop a continuous fusion reaction that could heat water, create steam and turn generators at a commercial fusion power plant, she said.

Meanwhile, the project is behind schedule and over budget, according to government reports.

Since 2005, when the laser-fusion experiment was isolated in a government program called the National Ignition Campaign, the project has spent more than $2 billion, or 25 percent more than its budget of $1.6 billion, according to the April Government Accountability Office report.

And, in those recent years, the project has fallen a year off schedule, the GAO says, with the expected completion date for the research now at the end of 2012.

Seaver, the National Ignition Facility spokeswoman, said the report mischaracterizes the lab's work.

"NIF has held all its milestones. It's held to its budget. The experiments are going just fine at NIF," she said. "They're going the way we thought they would."

Construction on the Livermore laser facility began in 1997, but the laser technology needed for the experiment has been 50 years in development, she said.

Meanwhile, other labs are working on fusion projects, too.

ITER, a project in France, for example, aims to use magnets and plasma, instead of lasers, to test nuclear fusion.

Research continues in non-fusion areas of nuclear power, as well.

Microsoft founder Bill Gates announced in February that he is funding research in a modified and more sustainable version of nuclear fission, the type of reaction that powers the world's existing nuclear reactors.

Fission involves splitting large, heavy atoms. Fusion, the star-making reaction being tried in Livermore, works the opposite way, sealing the nuclei of smaller atoms together.

The Livermore lab says it could get its fuel -- the two isotopes of hydrogen -- from seawater.

The process for extracting large amounts of deuterium and tritium from water has not been perfected, but the lab says the supply of these materials is nearly limitless.

"One gallon of seawater would provide the equivalent energy of 300 gallons of gasoline; fuel from 50 cups of water contains the energy equivalent of two tons of coal," the Livermore project's website says.

Unlike burning coal and natural gas, nuclear power does not produce greenhouse gases.

Doubts and optimism

Critics of Livermore's fusion research say it's too expensive and too theoretical.

The world needs to employ existing fixes for climate change rather than looking for a technological silver bullet that will prove to be too expensive for commercial energy production anyway, said Thomas B. Cochran, a senior scientist and nuclear physicist at the Natural Resources Defense Council, an environmental group.

"If you want to do [research and development] to alleviate climate change, you have to have technologies that can be brought online soon," he said. "We don't have much time to turn this around."

Even if the facility's lasers do create a fusion reaction, the lab is still a long way from becoming a commercial power plant, he said.

"It's not going to be competitive," he said. "It's crazy to go down that road. It's kind of fun and interesting -- graduate student projects designing these concepts. But they waste a lot of money in thinking [nuclear fusion] is going to contribute to society."

Nevertheless, the scientists in Livermore remain optimistic.

Van Wonterghem holds out hope for an energy miracle from fusion and has invested his entire career in the idea. Seaver believes that what's happening at the lab is historic.

"This is something you're going to tell your grandchildren about," the spokeswoman said on a recent tour of the lab. "You were here when they were about to get fusion ignition.

"It's like standing on the hill watching the Wright brothers' plane go by."

 

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ha ha

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