Introduction: Fusion

-Nuclear fusion is the process by which two light nuclei collide to form a larger nuclei, a loss of mass, and a large amount of energy. The difference in mass between reactants and prodcuts corresponds directly to the amount of energy released, E=mc^².

-The only requirement for fuel in a fusion reaction is that the nuclei must have a nuclear charge low enough to allow repulsion to be overcome, and the reaction to proceed.

-"Toroidalnaya Kamera ee Magnitnaya Katushka," or "Toroidal Chamber and Magnetic Coil"

-Depends on external windings for generating a strong toroidal magneticfield (in the direction along the doughnut).

-Combination of toroidal and poloidal magnetic fields generates an overall nested helical structure which is necessary to keep the plasma stable.

-Presently the leading candidate design for a future "working" magnetic fusion device.

- Magnetic confinement fusion devices are designed to confine hot, dense plasma for a sufficient period of time (a few seconds) for nuclei to fuse by overcoming their natural repulsive forces.

-An operating fusion energy reactor must attain sufficiently high energy density for the fusion to become self-sustaining (ignition) and generate economically significant energy gains.

-Due to the coupling of ionized particles and fields, any plasma system exhibits coherence and must be treated as an interactive system and not simply as an aggregate of parts.

-In plasma systems, a wide variety of forces and instabilities can oppose efforts at confinement.

-Basic research has enabled experiments that are 1,000,000 times better in overall performance than devices used only 20 years ago.

-Fusion is routinely produced in current experiments and we are now on the threshold of "burning plasma" experiments that will allow the construction of useful fusion power plants.

The fusion of a deuterium nucleus (deuteron) and a tritium nucleus (triton) which releases a neutron and produces a helium nucleus (protons shown in yellow, neutrons in blue)

-In an inertial confinement fusion reaction, energy is rapidly applied to the surface of the fusion capsule which causes the solid surface to vaporize or turn into a gas.

-Upon vaporization this material swiftly moves away from the remaining capsule material in a rocket-like manner.

-This projection of gas away from the surface creates shock waves that move through the capsule, compressing and heating the interior hydrogen isotopes.

-Using this technique it is possible to create conditions, similar to that in a star, which are necessary for fusion to occur.

-As the materials fuse they give off energy, that causes the other hydrogen nuclei to heat up and begin to expand.

-This expansion is limited by the tendency of the shock waves to continue compressing the material from the outside, otherwise known as inertia.

a. Application of laser to surface, creating a plasma

b. Rocket-like blast of gaseous surface material creating shockwaves that compress and heat interior

c. Initiation and continuation of fusion reaction in interior of capsule

-Cold fusion or low-temperature fusion, nuclear fusion of deuterium, an isotope of hydrogen, at or relatively near room temperature.

-Fusion, the reaction involved in the release of the destructive energy in a hydrogen bomb, requires extremely high temperatures, and investigations of fusion as a possible energy source have focused on the problems involved in designing an apparatus to contain and sustain such a reaction.

-In 1989 B. Stanley Pons and Martin Fleischmann, chemists at the Univ. of Utah, announced that an experiment conducted at room temperature using platinum and palladium electrodes immersed in heavy water (deuterium oxide) had produced excess heat and other by-products that they ascribed to a fusion reaction.

-Attempts to replicate their experiment produced initially conflicting results, but several early announcements of experimental confirmation were later retracted.

-Pons and Fleischmann were also later criticized for having skewed data to show the emission of gamma rays at an energy level typical of fusion.

-Research into the possibility of cold fusion, by Fleischmann and others, nonetheless continued, because of intriguing but inconclusive experimental results and because of the desirability of producing relatively nonpolluting fusion energy in quantity at any temperature.