The National Ignition Facility: An Energetic Defense
This past Friday, a few thousand folks attended Lawrence Livermore National Laboratory to see dignitaries including California Governor Arnold Schwarzenegger and U.S. Senator Dianne Feinstein dedicated the world's newest and most powerful laser, the National Ignition Facility (NIF).
Governor Schwarzenegger, clad in a pink tie– an odd sartorial choice for dedicating this giant hulk of a building housing 500 trillion watt laser housed within– nevertheless succeeded in channeling at least some of his Hollywood days. When they originally visited the facility last November, "we were so excited that we said, 'We'll be back.'"
The project's goal is to focus 192 laser beams onto a BB-sized capsule of hydrogen fuel in order to heat it to the point of ignition, that is, to achieve a nuclear fusion reaction where more energy comes out of the capsule than is put in. Fusion is the common process for creating energy in the Sun, and has been demonstrated on Earth both in the apocalyptic specter of thermonuclear weapons and in the more hope-inspiring form of plasma reactors such as those at the Joint European Torus (JET) in Britain. However, ignition has yet to be demonstrated, as JET requires a constant influx of energy greater than anything it is capable of producing. If all goes well within the next several months, ignition could be achieved at NIF as early as 2010.
For all of these exciting aspirations and promise of new technology, the press' reaction to NIF throughout the twelve years of its construction has been often lukewarm, and at worst scornful. Some of this has been deserved, and it is certainly true that the facility's $3.5 billion dollar construction cost is a hard price tag to swallow.
However, NIF is a worthy scientific cause and might well turn out to be an excellent investment. To put things a little bit into perspective, other large science projects are similarly expensive. The Large Hadron Collider (LHC) at CERN and the Hubble Space Telescope have both been estimated at about $6 billion. Dianne Feinstein argued in the past (and reminded the audience at Friday's dedication) that Enron needlessly cost $9 billion during the California Energy Crisis. Put another way, with $9 billion you could (a) experience rolling blackouts while Enron power traders cheer for wildfires ravaging your countryside, or (b) assemble the world's most powerful laser and use it to bring the nation to the brink of being able to replicate, in a controlled manner, the sorts of reactions that power the Sun. Twice.
The physics promise of the NIF, meanwhile, is truly fascinating on all three fronts of NIF's stated goals: energy production, basic research, and national security.
Fission reactors, which extract atomic energy from the splitting of large atoms such as uranium, have been a viable source of energy since 1954. However, the waste they produce remains radioactive for thousands of years. Potential fusion plants, on the other hand, would operate by an altogether different mechanism: the merging of much smaller hydrogen atoms. Radioactive byproducts are still generated, but the timescale for their radioactivity is shorter, on the order of 10 to 20 years.
A significant line of inquiry has already been pursued toward commercially viable nuclear fusion at JET and its planned successor, ITER. Such experiments employ powerful magnetic fields to maintain hydrogen plasma in a confined space and heat it to the point of fusion as it soars around inside a doughnut-shaped ring.
NIF serves as a valuable compliment to these magnetic confinement experiments. Instead of forcing a fusion reaction to perpetuate using costly magnetic fields, the NIF laser will attempt to blast its fuel with so much energy in such a short time period that the fuel will have no time to expand before it undergoes fusion. "If it works, developments at NIF would entirely reshape the dialogue on nuclear fusion energy," said Brian MacGowan, a NIF Program Director.
Even the most optimistic estimates place the viability of these types of energy sources 20 years into the future. NIF itself will never be able to function as a power generator even if all experiments performed at the facility proceed exactly as planned. The raw potential for such power extraction is nevertheless tantalizing.
Additionally, there is basic research potential for NIF beyond fusion power. Stars are typically easy to observe from a distance but inevitably too far away and too inhospitable to explore up close. A miniaturized version of the reaction as created in the NIF target bay could provide an interesting model system. There is no way to tell, but it could be that hand in hand with this ability comes a better understanding of some of the deepest outstanding questions in physics as well, such as the nature of dark energy and dark matter.
NIF also offers a unique way for the U.S. to test the effects of nuclear weapons without violating the Comprehensive Nuclear Test Ban Treaty. NNSA Administrator Tom D'Agostino noted at the dedication that, particularly as the United States' nuclear arsenal ages, this will provide the U.S. with invaluable data.
We may emerge from this economic crisis a poorer, humbler country. Still, I hope that we are not yet so humble that we have lost the ability to dream big, and not yet so poor that we can no longer actively pursue at least a few of those dreams.
37.679754 -121.698912Tags: california, fusion, hydrogen, laser, llnl, NIF, Science