This article was taken from the August issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online
It's mid February in California's Livermore Valley wine country, and the sky above the dormant vineyards is candyfloss blue. An hour or so northwest of here, past lazy sloping green hills and pastures, San Francisco shimmers on the bay. Here, a wayward oenophile would have no idea that, just up the road from his tasting-room crawl, one of the most groundbreaking scientific achievements in human history is being attempted: to make a miniature Sun on Earth.
Tucked away in the sprawling 260-hectare campus of Lawrence Livermore National Laboratories is a windowless ten-storey building bearing the insignia "National Ignition Facility" (NIF). Here, scientists have constructed the most powerful and advanced laser ever built: 192 beams delivering a blast of nearly two million Joules, equivalent to the energy consumed by 20,000 100-Watt lightbulbs in a second.
Scientists plan to focus all that energy on to a target the size of a peppercorn, creating magnitudes of heat and pressure hitherto unknown outside the centre of stars: 100,000,000°C, and pressures more than 100 billion times those in the Earth's atmosphere. The hope is that it will be enough not only to induce nuclear fusion reactions -- the same process that makes stars burn for millions of years -- but that those reactions will generate more energy than that put in to start the reactions.
The repercussions of achieving that milestone -- called "ignition" -- are incalculable. Unlike the fission reactions that drive today's nuclear power plants, fusion would create no nuclear waste, and the components for its fuel -- primarily deuterium, and just 30 litres of water -- could provide the same energy as 9,400 litres of petrol. NIF's director, Ed Moses, has called it nothing short of the Holy Grail of energy. "We're very optimistic," says Brian MacGowan, NIF's director of inertial confinement fusion. In an empty conference room just beyond NIF's main entrance, the soft-spoken grey-haired physicist holds out a clear plastic capsule containing a demonstration version of one of NIF's targets: a tiny golden "hohlraum" (hollow area -- think of a beer can shrunk to a centimetre in size) containing a minuscule red orb of deuterium and tritium."We have a design for the target we're going to shoot later this year where we will," he says, "for the first time, get conditions for ignition."
But since construction began in 1997, the federally funded NIF has been plagued with controversies and setbacks. It opened in March last year at a cost of $3.5 billion (£2.25 billion), nearly four times the original estimate. Its original director resigned after it was discovered he'd falsely allowed the laboratory to believe he had completed his PhD coursework. In 2000, the Natural Resources Defense Council -- an environmental action group -- sued NIF for failing to be transparent when consulting for funding. Five years later, NIF came very close to dying when the US Senate voted to pull funding after construction delays and ballooning costs.
Meanwhile, in Europe strong contenders were arising in the race for fusion-energy glory: the Laser Mégajoule project in Bordeaux, France, will use a design similar to NIF's but with 240 beams, and is due to complete in 2012. Elsewhere in France there's ITER (originally the International Thermonuclear Experimental Reactor), a €12 billion (£10 billion) project in Provence that uses superconducting magnets to induce fusion in a plasma. "ITER is the real deal for fusion energy," says Ed Morse, professor of nuclear engineering at the University of California, Berkeley. "Or at least it's the only hope."
Regardless of who wins the race, discovering a way to produce safe, sustainable, carbon-free energy has become the most pressing issue of the day -- a fact underscored last February when, at the annual TED Conference in Long Beach, California, Microsoft founder Bill Gates chose to talk not about software development, but about energy and climate. "An energy breakthrough is the most important thing," Gates said. "It would have been, even without the environmental constraint, but the environmental constraint just makes it so much greater."
The world no longer has a grand scientific trophy -- a space race -- to pursue. It has an energy crisis. If NIF finds a solution -- and it insists it will be first to achieve ignition -- MacGowan and his colleagues will share a degree of celebrity not unlike that of Neil Armstrong, whose boot first stirred virgin moondust. NIF has a saying: "The world is watching," and it's more than just a slogan. Sitting across the cherry-wood conference-room table in a coral-coloured shirt, MacGowan recalls the time two years ago when that saying became acutely palpable. "I was at a conference in Japan," he says, "and I got told that everyone was depending on us.
It's exciting. If you have a way of generating the energy that people need without carbon build up or the generation of long-duration nuclear waste, that would be a real game-changer."
Fusion works in the following way: at the centre of a star, the heat and density is so great that hydrogen nuclei overcome their strong electrostatic repulsion and fuse together to form helium nuclei. In the process, an extra neutron is ejected from the reaction, and the end products are lighter than the original mass.
That missing mass is converted to energy (Einstein's famous E = MC2 incarnate) which powers the chain reaction, fuels the cycle, and keeps stars burning. Scientists have been trying to replicate the process on Earth for virtually as long as they've understood it.
The problem, of course, is that the heat and pressures required to get fusion to work in such a way that it produces net energy don't exist outside the centre of a star. Even when scientists recreate it in laboratories, it's extremely difficult to contain and sustain. Deuterium (2H) and tritium (3H) atoms have proved to be the easiest fusion reactions to achieve on Earth -- the kinds likely to end up in first-generation fusion reactors. Fusing them together produces an alpha particle, which deposits its energy locally, and adds heat and a neutron. In the process, the nuclei of the deuterium and tritium increase their size and, with it, the probability of a fusion reaction. They also each have the smallest possible positive charge (since hydrogen has only one proton), making it relatively easy for the two nuclei to overcome their repulsion and fuse together.
In order to make those nuclei fuse, NIF focuses its 192 beams into a tiny capsule made of gold and boron -- a process called inertial- confinement fusion (ICF). When they fire, their ultraviolet light gets converted to X-rays in the capsule, which turns into something like a tiny microwave oven that compresses that peppercorn- sized target of deuterium and tritium down to the width of a human hair until it explodes in a burst of neutrons and energy. It all happens in 20 nanoseconds.
But if NIF manages what has so far been impossible -- to net more energy through fusion than the energy it took to induce it -- it will still have to find a way to make these reactions occur quickly and efficiently enough to drive a power plant. Annihilating one pellet won't cut it -- it will need something like 600 a minute.
The neutrons and energy would heat a blanket of molten salt around the target chamber and, from there, the process will work much as in today's fission reactors -- the heat boils water, and steam drives turbines. Regardless of if and when it happens, it won't happen at NIF, MacGowan says, because the facility isn't set up to handle it. NIF's legacy is getting those lasers to converge with unheard-of power and unprecedented accuracy. And even though construction crews only broke ground in 1997, that legacy is hard-won.
In 1960, when the first laser was demonstrated, MacGowan says, "several scientists had the idea that you could use it as a power source to implode isotopes of hydrogen and get them to ignite." By the 80s, scientists realised that in order to get a capsule to ignite it would require energy in the order of a million Joules. By the 90s, the US Department of Energy challenged Livermore Labs, then using its 30,000-Joule NOVA laser, to demonstrate various aspects of inertial- confinement fusion and show what the optimum-sized facility should be. "NOVA had enough power for scientists to study how well a laser can deposit its energy into a target. The short pulse of the laser has to be converted into X-rays, then symmetrically implode the capsule. They showed they could probably do the same thing on a laser closer to NIF's size," he says.
In 1999, with NIF already $350 million over budget, The New York Times quoted US energy secretary Bill Richardson as saying that "there may have been an effort of concealment" by NIF management, in the hope that problems would remain undetected. That year, El Niño rains flooded the NIF site and caused a substantial setback. A month later, a digger uncovered the remains of a 16,000-year-old mammoth that had to be excavated by an archaeological team from the University of California at Berkeley.
Meanwhile, NIF's enormous ten - metre, 130-tonne target chamber was being built. Its 6,800-kilogramme, ten-centimetre-thick flat aluminium plates were pieced together like segments of a volleyball and then hoisted on to a concrete pedestal inside the target building in June 1999.
But that year, another bizarre setback occurred: officials at Livermore Laboratories and the Department of Energy received anonymous faxes claiming that the lab's associate director of lasers (in charge of the then $1.2 billion programme to build the NIF), E Michael Campbell, had lied about his PhD. Although he had completed his coursework at Princeton when he joined Livermore in 1977, he'd never finished his dissertation. A year later came the Natural Resources Defense Council lawsuit.
Nevertheless, by August 2002, NIF scientists had pressed ahead and aligned the 300-metre beamline. But NIF's woes were far from over. Three years later, when NIF's new estimated cost of completion came in at more than twice its original estimate of $900 million, the Senate voted to pull the plug. If Congress hadn't come through, it would have spelled the end. When NIF finally came online in March 2009, it was seven years behind schedule and had a $3.5 billion price tag, nearly four times its estimate, for a building the size of two soccer pitches, containing more than 3,000 40-kilogram slabs of laser glass, 26,000 smaller glass optics, 3,000 laser mirrors and lenses, and 1,000 crystalline optics.
That month, NIF scientists fired the first shot with all 192 beams -- a two-megajoule blast that lasted just a few nanoseconds but amounted to 500 trillion Watts of power, roughly 1,000 times the peak generation power of the US national grid. On August 25, scientists shot a gas-filled hohlraum for the first time.
At the access-restricted entrance to NIF's inner core, Wired is met by Bruno M Van Wonterghem, NIF's cheery Belgian operations manager. We proceed, hard hats on, into a huge room with a polished concrete floor known as Laser Bay One. NIF has two laser bays, each containing 96 laser amplifiers. The plastic tubes high above our heads look as though they could be plumbing. In truth, each of these beams represents the world's strongest laser -- around 25,000 Joules apiece (the most powerful commercially available lasers are somewhere in the order of a single Joule; NIF is as powerful as two million of these combined).We wander over white sticky pads that pull dust from the soles of our shoes and end up in the control room, a glass fishbowl full of bustling scientists at computer consoles who gaze up intermittently at giant screens flashing data.
It looks like Nasa's Mission Control.
An ignition attempt takes a day to set up: two or three hours to prepare the lasers, but as many as 24 just to ready and position the target, which extends into the spherical chamber on the tip of what looks like a giant metal pencil. MacGowan describes a typical set of events at NIF in the autumn: at 5am, a target crew would start installing a target; by mid-morning, they would begin cooling the target to cryogenic temperatures of 20 Kelvin, close to absolute zero; by late afternoon, they begin setting up the lasers and aligning diagnostics to the target. Then that night -- probably late -- they would fire the shot (NIF has fired around 60, MacGowan says, since its first test with all beams last March). For everything to work, about 60,000 control points - from mirror motors to valves -- must be in the proper position. The 14-person crew conducts low-energy tests to make sure the pulse shape is viable, then they charge up the amplifiers. The computer starts a countdown.
Van Wonterghem was NIF's first shot director in 2002. "It's really exciting during the last few seconds of the countdown," he says, letting go a childlike laugh.
The phrase "world's most powerful laser" conjures images of an enormous chrome-clad death ray -- the kind one might expect to see rising from the remote island lair of some Bond supervillain. So the NIF laser, at first glance, could be a disappointment. For starters, for all but a tiny portion of its journey its beam is totally invisible -- it starts out as infrared and ends in the ultraviolet spectrum. As Von Wonterghem walks Wired through a labyrinthine series of doors to the Master Oscillating Room, we learn something else: NIF's "death ray" is born here, as two oscillating infrared pulses in a pair of toaster-sized black boxes -- "the same used in telecommunications industries", Von Wonterghem says. Their energy: barely one nanojoule -- "about the energy of a laser pointer".
Turning that trickle into a deluge requires a tortuous journey through a $3.5 billion machine. The oscillators fire twin pulses that last only 20 billionths of a second, making a beam of light about six metres long. Each beam is amplified and split into 48 identical pulses, which race into a wall of black boxes with flickering green LEDs called "pulse shapers" that optimise the beams and send them out over the top of the laser bays through fibre-optic cables. In the laser bays, those pulses are amplified to a factor of ten billion. As one pass isn't enough, the pulse bounces back and forth through slabs of specially grown crystals that can change their polarisation almost instantaneously. Timed right, the laser beams can bounce back and forth, collecting energy and gathering strength, until they're released and split into 192.That number is split into 24 groups of eight, each group taking a separate path through the main amplifier.
The "amplifier" is actually a row of five enormous slabs of pink laser glass that get bathed in blinding white light from xenon flash lamps. The glass is smeared in such a way that all that light gets absorbed into the slabs and then picked up by the beams as they pass through. NIF's computers direct the beam back and forth four times through 11 sets of laser amplifier glass for another boost of energy. The beam tubes are filled with argon. It's such a distance that the cross-section becomes warped and inefficient, so NIF scientists devised a deformable mirror that can custom-correct the shape of the beam and warp it back to being uniform again. On the last pass, the laser light exits and gets redirected to the "switchyard". The original laser pulse is now a quadrillion times stronger than when it started. The parallel beams of lasers get turned into conical shapes and then, just before converging on the enormous metal sphere, they pass through a series of optics that convert the infrared light to blue-green light and then ultraviolet. All the beams arrive within 30 picoseconds (30 trillionths of a second) of one another, and they have a precision of 50 micrometres.
NIF's primary purpose was never clean fusion energy: it was nuclear warheads. Like its sister labs, Los Alamos in New Mexico and Sandia, across the street, Lawrence Livermore National Laboratories is primarily focused on US national security. To that end, the technology behind NIF was sold to Congress as helping maintain the viability of America's ageing nuclear-weapons cache. The intention is that, by modelling what happens in a controlled fusion reaction, we can better predict how nuclear warheads might behave (the US hasn't detonated one since 1992). It so happens that the research is just as useful for understanding astrophysical phenomena (NIF's secondary stated goal) and, of course, producing clean energy (its third). Nuclear fusion is the underlying process behind all three.
And although NIF's communication director Lynda Seaver insists the facility's goals are limited only to "testing the safety, security, and reliability" of America's more than 10,000 nuclear warheads, local activists believe NIF has gone beyond maintaining them and, instead, is actually improving them. Livermore has long focused on nuclear-weapon design. In 1957, it began developing the warhead for the US Navy's Polaris missile. During the Cold War, Livermore designed ever more advanced warheads. The Lance surface-to-surface tactical missile. The Spartan antiballistic missile. The Minuteman ICBM. TheW87Peacekeeper. TheW89Tomahawk. In 2007, the US government said that it had selected a design from Livermore for the first new US nuclear warhead in two decades.
Beyond the politics, there remain plenty of practical hurdles to overcome. To generate the kind of energy to justify the cost of such a facility, Van Wontergehm says, you'd have to fire the motor ten times a second -- like a 600 rpm motor -- to get the equivalent of a 500 megawatt or a gigawatt power plant. "So you'd have to shoot in the targets because you can't have a positioner bring them in," he says.
According to MacGowan, those targets each costs $250,000. "There is [also] the matter of making the driver system capable of delivering 300 million shots per year with at least ten per cent efficiency," Morse says. "And costing less than a billion dollars.
Then there's the blanket, which must survive as many loads of pulsed neutrons, gammas, and heat. And not leak tritium."
Ed Morse and others have more confidence in France's ITER, which is using magnetic fields to confine superheated plasma in which fusion reactions occur. If clean energy -- not safer warheads -- is the ultimate goal, that scheme might leave NIF in the dust. "Several magnetic confinement devices -- in the US, Europe and Japan -- have produced millions of Watts of fusion power this way," says Richard Hazeltine, director of the Institute for Fusion Studies at the University of Texas at Austin. "The ITER experiment will explore the practicality of magnetic fusion on a much larger scale than any previous experiment. The issue is whether a magnetic fusion power plant will be attractive to utility companies. Will it be too expensive? Too complicated? Too difficult to maintain? These are hard questions. They will be answered only partly by ITER."
NIF's scientists don't need to be reminded of what's at stake. "It's actually intimidating that everyone's watching us," MacGowan says. "And I don't think we're going to have any excuses to fail.
We have this wonderful machine, this wonderful facility, a lot of really talented people -- and if we don't succeed, we'll be at fault."
For now, the 130-tonne sphere of polished metal at the heart of NIF's star-making machine rests there -- silent, like a promise.
Ian Daly is a writer who lives in New York
This article was originally published by WIRED UK
