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

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    The idea of using a “magnetic bottle” to create fusion is not new. It goes back to the 1950s, in fact. But why has it taken so long, with so many delays, to commercialize fusion power?
    The problem is that the magnetic field has to be precisely tuned so that the gas is compressed evenly without bulging or becoming irregular. Think of taking a balloon and trying to compress it with your hands so that the balloon is evenly compressed. You will find that the balloon bulges out from the gaps between your hands, making a uniform compression almost impossible. So the problem is instability and is not one of physics but of engineering.
    This seems strange, because stars easily compress hydrogen gas, creating the trillions of stars we see in our universe. Nature, it seems, effortlessly creates stars in the heavens, so why can’t we do it on earth? The answer speaks to a simple but profound difference between gravity and electromagnetism.
    Gravity, as shown by Newton, is strictly attractive. So in a star, the gravity of the hydrogen gas compresses it evenly into a sphere. (That is why stars and planets are spherical and not cubical or triangular.) But electrical charges come in two types: positive and negative. If one collects a ball of negative charges, they repel each other and scatter in all directions. But if one brings a positive and negative charge together, you get what is called a “dipole,” with a complicated set of electrical field lines resembling a spider web. Similarly, magnetic fields form a dipole; hence squeezing hot gas evenly inside a doughnut-shaped chamber is a fiendishly difficult task. It takes a supercomputer, in fact, to plot the magnetic and electric fields emanating from a simple configuration of electrons.
    It all boils down to this. Gravity is attractive and can compress gasevenly into a sphere. Stars can form effortlessly. But electromagnetism is both attractive and repulsive, so gases bulge out in complex ways when compressed, making controlled fusion exceedingly difficult. This is the fundamental problem that has dogged physicists for fifty years.

    Until now. Physicists now claim that the ITER has finally worked out the kinks in the stability problem with magnetic confinement.
    The ITER is one of the largest international scientific projects ever attempted. The heart of the machine consists of a doughnut-shaped metal chamber. Altogether, it will weigh 23,000 tons, far surpassing the weight of the Eiffel Tower, which weighs only 7,300 tons.
    Two types of fusion. On the left, lasers compress a pellet of hydrogen-rich materials. On the right, magnetic fields compress a gas containing hydrogen. By midcentury, the world may derive its energy from fusion.
    The components are so heavy that the roads transporting the equipment have to be specially modified. A large convoy of trucks will transport the components, with the heaviest weighing 900 tons and the tallest being four stories high. The ITER building will be nineteen stories tall and sit on a huge platform the size of sixty soccer fields. It is projected to cost 10 billion euros, a cost shared by seven member states (the European Union, the United States, China, India, Japan, Korea, and Russia).
    When it is finally fired up, it will heat hydrogen gas to 270 million degrees Fahrenheit, far surpassing the 27 million degrees Fahrenheit found in the center of the sun. If all goes well, it will generate 500 megawatts of energy, which is ten times the amount of energy originally going into the reactor. (The current record for fusion power is 16 megawatts, created by the European JET (Joint European Torus) reactor at the Culham Science Center, in Oxfordshire, UK.) After some delays, the target date for break-even is now set to be 2019.
    The ITER is still just a science project. It is not designed to producecommercial power. But physicists already are laying the groundwork for the next step, taking fusion power to the marketplace. Farrokh Najmabadi, who leads a working group looking into commercial designs for fusion plants, has proposed ARIES-AT, a smaller machine than the ITER, which would produce a billion watts at roughly 5 cents per kilowatt-hour, making it competitive with fossil fuels. But even Najmabadi, who is optimistic about fusion, admits that fusion won’t be ready for widespread commercialization until the middle of the century.
    Another commercial design is the DEMO fusion reactor. While the ITER is designed to produce