For years, scientists have tried to make fusion a viable source of renewable energy for the world. In the sun, hydrogen molecules are smashed together to form helium nuclei and tremendous energy that allows the sun to give off its brilliant light. Scientists have tried to recreate this fusion reaction on a smaller scale so that they can produce tremendous amounts of energy and essentially solve our world's energy problem.
In order for an energy source to be viable, the reaction involved must be able to produce more energy then the reaction requires. While we have been able to create fusion reactions in a laboratory (and not just in the hydrogen bomb), the fusion reactions not occurring in hydrogen bombs fail to produce even a half of the energy they require. More frustratingly, every time scientists think they have gotten to the point of achieving a successful fusion reaction (which they have dubbed ignition), rather than one which yields to little energy, they find that they must overcome some new curve ball. In 2009, scientists completed simulation programs, pumped with millions of lines of code and tons of equations and data from careful experiments and measurements, that were designed to predict the behavior of a fusion reaction that would occur in the National Ignition Facility (NIF). The programs were run through the world's fastest supercomputers, and even those took days to weeks to run through the simulations and return the results.
Encouragingly, the simulations predicted that lasers fired from all directions at a small pellet of hydrogen fuel would be able to implode the pellet and create a brief, self-sustaining fusion reaction that would produce over 100 times the energy needed by the lasers to induce the reaction. Sounds promising, right? Well, sadly, when the simulations were put to the test, ignition failed miserably, and ever since, scientists have tweaked the process and the hardware to get better results. While they have gotten progressively closer to ignition, they still have a long way to go, and with billions of dollars already spent on the project, scientists and politicians are beginning to wonder if fusion is still a practical option. Now, fusion projects are springing up around the world, with everyone looking for a new or better way to achieve fusion and ultimately achieve ignition. The University of Rochester (right in our backyard!) has been experimenting with the Omega laser to create fusion reactions by firing the lasers directly at the hydrogen pellet, rather than at a hohlraum, or target container, as the NIF laser has. Another project, called ITER, aims to create fusion using powerful electromagnets rather than lasers.
The quest for ignition is an uphill battle, with nature throwing curve balls continually at hardworking physicists. While some scientists (and especially politicians) are beginning to wonder if fusion will ever be a practical source of energy, I am still optimistic. If we can finally get it working, we could solve our energy problem almost completely, so even with a multi-billion dollar price tag, I think the research, trial-and-error, and even the disappointments will all be worth it someday.
For more information on fusion and the quest for ignition, see the article here: