NEWS&ANALYSIS therapy for genetic intellectual disabilities like Down syndrome, but also campaigned tirelessly against abortion—which made him a lightning rod among the left wing in France. (Lejeune was friends with Pope John Paul II and the Vatican is now considering a request to beatify him.) In its statement, the foundation lashed out at Gautier’s supporters for trying to discredit an ideological opponent. It said Gautier, at her age, can’t be

blamed for her “confusion,” but called stories backing her version of events in Le Monde and Libération—both left-wing papers— “ideological terrorism.” Gilgenkrantz, who convinced Gautier to tell her story in 2009, says it should be told regardless of the politics involved. To her, it’s one more tale of a female scientist wronged at a time when French science was still very sexist. “This is a story that must be known,”

she says, “in the name of women.” But Bernard Dutrillaux, who worked in Lejeune’s lab from the mid-1960s until the early 1980s, believes that some scoresettling may be going on. “Lejeune made a lot of enemies” among his peers, he says. Still, he condemns the foundation’s legal maneuvers. Both sides, Dutrillaux says, should know better than to fight such “petty rear-guard battles.” –ELISABETH PAIN


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Laser Fusion Shots Take Step Toward Ignition As it approaches its fifth birthday, the To reach the extreme conditions cool fuel would compress to a higher density National Ignition Facility (NIF), a troubled necessary for fusion, NIF relies on a laser the at the end. The downside was that the slower laser fusion lab in California, has finally size of a football stadium. It produces 192 speed allowed the capsule time to break up. produced some results that outsiders can get ultraviolet beams in a pulse lasting just 15 So they decided to try a pulse that started enthusiastic about. In a series of experiments nanoseconds that can deliver 1.9 megajoules off with a higher power to implode faster and last year, NIF researchers produced yields (MJ) of energy, roughly the same as the ended the pulse sooner, after 15 ns. Although of energy 10 times greater than achieved kinetic energy of a 2-ton truck traveling such a “high foot” pulse wouldn’t produce before and demonstrated the phenomenon at 160 kilometers per hour. The ultraviolet such high density at the end, the researchers of self-heating that will be crucial if fusion beams are converted into x-rays, which then hoped it would help control the mixing. is to reach its ultimate goal of “ignition”—a compress a fuel capsule, a hollow plastic A laser shot carried out on 13 August last self-sustaining reaction that produces more sphere smaller than a peppercorn, containing year proved them right, with a huge jump energy than it consumes. “This is a very 0.17 milligrams of frozen deuterium and in energy output. Another two shots, on 27 significant achievement, and September and 19 November, did it’s a very good place to start for even better, actually producing going to higher yield,” says Stemore energy (14.4 and 17.3 kJ) ven Rose of the Centre for Inerthan was deposited in the fusion tial Fusion Studies at Imperial fuel at the start (11 and 9 kJ), the College London. first time that has been achieved NIF, at Lawrence Livermore in a laser fusion experiment. “We National Laboratory in Caltook a step back from what had ifornia, aims to release enormous been tried before and that gave amounts of energy by fusing us a leap forward,” says NIF team together nuclei of two isotopes of leader Omar Hurricane. hydrogen: deuterium and tritium. Importantly, the team also saw It heats the nuclei to enormous a self-heating phenomenon that temperatures and pressures so will be vital for increased yield. that they smash together with Fusion reactions produce alpha enough force to overcome their particles (helium nuclei); when mutual repulsion. On the up. A chart of NIF’s fusion shots since mid-2011 shows that a “high-foot” reactions start in the core of the NIF has struggled to get laser pulse has boosted yields. Dates are given as YYMMDD. fuel, the alphas help by heating its process to work, however the surrounding cooler fuel up (Science, 21 September 2012, p. 1444). tritium. The aim is to produce a ball of fuel to reaction temperature. “This is the first Last year, instead of going flat-out for with a temperature of 50 million kelvin and strong indication of that bootstrap process,” ignition, researchers there adopted a more 100 times the density of lead, conditions that Hurricane says. exploratory approach to try to identify the can spark fusion. However, NIF is far from real gain (more problems. The data from last year’s efforts, Researchers realized last year that during energy out than the total input) because so published this week in Nature and last week this implosion, the plastic capsule was much energy is lost converting the laser beams in Physical Review Letters, are the first sign breaking up and mixing with the fuel, making to x-rays and training them on the capsule. that this approach is working. “It’s a nice it harder to achieve fusion. So they adjusted the The team’s best shot had a gain of less than result,” says Robert McCrory, director of timing of the laser pulse. Traditionally, it ran at 0.01. But there is general optimism following the Laboratory for Laser Energetics at the a low power for most of its 20 nanoseconds the past year’s progress. “These are the right University of Rochester in New York, who to get the implosion moving without heating experiments to do,” says Michael Campbell, quickly cautions that NIF is still a long up the fuel and then finished with a burst of a former NIF director now at Sandia National way from ignition. “People expecting a high power for the final spark. The rationale Laboratories. “Who knows how far they can breakthrough soon will be disappointed.” for this “low foot” approach was that the still- take this?” –DANIEL CLERY


VOL 343

Published by AAAS

14 FEBRUARY 2014


Energy. Laser fusion shots take step toward ignition.

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