Fusion: Harnessing the Power of the Sun Essay -- physics fusion

History It has been a well-accepted fact that the sun is a source of great power since the early part of this century. In 1929, scientists first theorized that the energy production in stars was created by fusion: nuclear reactions involving light elements reacting to form heavier elements. By the late thirties, H. Bethe had analyzed most of our sun's nuclear fusion cycle. Fusion in our sun is caused when deuterium and tritium, both Hydrogen isotopes, react (in the presence of large amounts of heat) to form Helium, energy, and an extra neutron. Man-made fusion reactions were thought to be impossible until the first uncontrolled fusion reactions were witnessed when nuclear bombs known as "George" and "Mike" were detonated in 1951 and 1952, respectively. Efforts to control fusion energy began in the 1950s. By 1955 scientists had witnessed the enormity of the task. A successful fusion reaction would not only require temperatures in excess of 50x106 K, but would also need to be isolated for a long enough time so the reaction could produce more energy than required to begin the reaction. The most promising fuels for fusion reactions are deuterium, and tritium. Deuterium and tritium both are hydrogen isotopes. Deuterium is a stable isotope and is naturally found in water, while tritium is very unstable, radioactive, and must be man-made. Several methods for containment exist. They include the Tokamak generator, inertial containment, and mirror confinement. The Tokamak Problems with early power plants led to the development of the Tokamak. An old design, known as the linear pinch method, suffered from large energy losses at the ends of the plant and macroscopic plasma instabilities. To overcome these problems, a new design ... ...llion degrees, the fuel ignites and fusion occurs. The reaction then spreads through the compressed capsule, producing energy several times greater than what was deposited by the beams. The majority of research so far involving this type of fusion has dealt with laser beams. These powerful flashes of light, with varied wavelengths and duration, are focused on the capsule to initiate fusion. However, our modern lasers are very inefficient. To be used in a commercial fusion plant, laser technology would first have to greatly improve. Another option in Inertial Confinement is ion beams instead of lasers. The ion beams are much more efficient, but are still very experimental. The biggest problem is the beam's short span. An intense enough beam to cause the reaction only lasts about 10 nanoseconds. To compensate, scientists must compress the beam and make it stronger.