Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100

500 megawatts for a minimum of 500 seconds, the DEMO will be designed to produce energy continually. The DEMO adds one extra step lacking in the ITER. When fusion takes place, an extra neutron is formed, which quickly escapes from the chamber. However, it is possible to surround the chamber with a special coating, called the blanket, specifically designed to absorb the energy of this neutron. The blanket then heats up. Pipes inside the blanket carry water, which then boils. This steam is sent against the blades of a turbine that generates electricity.
    If all goes well, the DEMO will go online in 2033. It will be 15 percent larger than the ITER reactor. DEMO will produce twenty-five times more energy than it consumes. Altogether, DEMO is expected to produce 2 billion watts of power, making it comparable to a conventional power plant. If the DEMO plant is successful, it could lead to rapid commercialization of this technology.
    But many uncertainties remain. The ITER reactor has already secured the funding necessary for construction. But since the DEMO reactor is still in its planning stages, delays are to be expected.
    Fusion scientists believe that they have finally turned the corner. After decades of overstatements and failures, they believe that fusion is within grasp. Not one but two designs (NIF and ITER) may eventually bring fusion electricity into the living room. But since neither NIF nor ITER is yet delivering commercial fusion power, there is still room for the unexpected, such as tabletop fusion and bubble fusion.
    TABLETOP FUSION
    Because the stakes are so high, it is also important to acknowledge the possibility of solving the problem from an entirely different, unexpected direction.Because fusion is such a well-defined process, several proposals have been made that are outside the usual mainstream of large-scale funding but that still have some merit. In particular, some of them might one day achieve fusion on a tabletop.
    In the final scene in the movie
Back to the Future,
Doc Brown, the crazy scientist, is seen scrambling to get fuel for his DeLorean time machine. Instead of fueling up with gasoline, he searches garbage cans for banana peels and trash and then dumps everything into a small canister called Mr. Fusion.
    Given a hundred years, is it possible that some breakout design may reduce huge football field–size machines to the size of a coffeemaker, like in the movie?
    One serious possibility for tabletop fusion is called sonoluminescence, which uses the sudden collapses of bubbles to unleash blistering temperatures. It is sometimes called sonic fusion or bubble fusion. This curious effect has been known for decades, going back to 1934, when scientists at the University of Cologne were experimenting with ultrasound and photographic film, hoping to speed up the development process. They noticed tiny dots in the film, caused by flashes of light generated by the ultrasound creating bubbles in the fluid. Later, the Nazis noticed that bubbles emitted from their propeller blades often glowed, indicating that high temperatures were somehow being produced inside the bubbles.
    Later, it was shown that these bubbles were glowing brightly because they collapsed evenly, thereby compressing the air in the bubble to enormously high temperatures. Hot fusion, as we saw earlier, is plagued by the uneven compression of hydrogen, either because laser beams striking the pellet of fuel are misaligned or the gas is being squeezed unevenly. As a bubble shrinks, the motion of the molecules is so rapid that air pressure inside the bubble quickly becomes uniform along the bubble walls. In principle, if one can collapse a bubble under such perfect conditions, one might attain fusion.
    Sonoluminescence experiments have successfully produced temperatures of tens of thousands of degrees. Using noble gases, one can increase the intensity of light emitted from these bubbles. But there is some controversy over whether it can achieve temperatures hot enough to produce nuclear fusion. The controversy stems from the work of Rusi Taleyarkhan, formerly of the Oak Ridge National Laboratory, who claimed in 2002 thathe was able to achieve fusion with his sonic fusion device. He claimed to have detected neutrons from his experiment, a sure sign that nuclear fusion was taking place. However, after years of work by other researchers who have failed to reproduce his work, this result, for the moment, has been discredited.
    Yet another