Fusion; September 1995; Scientific American Magazine; by Furth; 3 Page(s)
During the 1930s, when scientists began to realize that the sun and other stars are powered by nuclear fusion, their thoughts turned toward re-creating the process, at first in the laboratory and ultimately on an industrial scale. Because fusion can use atoms present in ordinary water as a fuel, harnessing the process could assure future generations of adequate electric power. By the middle of the next century, our grandchildren may be enjoying the fruits of that vision.
The sun uses its strong gravity to compress nuclei to high densities. In addition, temperatures in the sun are extremely high, so that the positively charged nuclei have enough energy to overcome their mutual electrical repulsion and draw near enough to fuse. Such resources are not readily available on the earth. The particles that fuse most easily are the nuclei of deuterium (D, a hydrogen isotope carrying an extra neutron) and tritium (T, an isotope with two extra neutrons). Yet to fuse even D and T, scientists have to heat the hydrogen gases intensely and also confine them long enough that the particle density multiplied by the confinement time exceeds 1014 seconds per cubic centimeter. Fusion research since the 1950s has focused on two ways of achieving this number : inertial confinement and magnetic confinement.