APPROACHES TO FUSION

The Tokamaks represent today the most promising and best understood approach to fusion. The review paper by Bickerton12 summarizes the status of Tokamak research in 1978. The physics of Tokamaks has been described by Artsimovich22. The name Tokamak is a Russian abbreviation of Toroidal Kamera Magnetik , i.e. Toroidal Chamber Magnetic . 

TABLE II — SUDAN S CLASSIFICATION SCHEME OF UNCONVENTIONAL APPROACHES TO FUSION... 

The Erice International School of Fusion Reactor Technology held its 1981 course on Unconventional Approaches to Fusion in combination with the IAEA Technical Committee meeting on Critical Analysis of Alternative Fusion Concepts . The two events took place in the second half of March with an overlap of a few days only. 

Comparison of a Tokamak reactor with a PWR can be founded on considerations of such a basic nature that it becomes almost automatic to ask how far the various unconventional approaches to fusion are exempt from the Tokamak s drawbacks. 

An unconventional approach to fusion deserves to be considered as an alternative to the Tokamak reactor if it appears to be exempt from some of the constraints which prevent the Tokamak from behaving more satisfactorily. At the cost of writing an unconventional foreword to this book, I shall try to review the limitations inherent in a Tokamak, and in doing so, I find it rather convenient to borrow a bit of the language of fission people viz. I shall use the so-called conductivity integral ... 

At this point, an unconventional approach to fusion deserves attention if, besides the feasibility, it has at least one of the following advantages with respect to the (Z), T) Tokamak ... 

Thermal Theory. The thermal approach to flame retardancy can function in two ways. Eirst, the heat input from a source may be dissipated by an endothermic change in the retardant such as by fusion or sublimation. Alternatively, the heat suppUed from the source maybe conducted away from the fibers so rapidly that the fabric never reaches combustion temperature. 

Another approach to nuclear fusion is shown in Figure 19.6. Tiny glass pellets (about 0.1 nun in diameter) filled with frozen deuterium and tritium serve as a target. The pellets are illuminated by a powerful laser beam, which delivers 1012 kilowatts of power in one nanosecond (10 9 s). The reaction is the same as with magnetic confinement unfortunately, at this point energy breakeven seems many years away. 

Benson and coworkers15, and the values differ somewhat. The differences probably reflect the small differences in the enthalpies of formation of the parent compounds used in the two cases (i.e., the differences between enthalpies of formation compiled by Benson and coworkers15 and those compiled by Pedley, Naylor and Kirby17) as well as different approaches to deriving the group contributions. The major differences probably arise from the different values used for the relevant enthalpies of fusion and vaporization. It should be emphasized that the derivation of group contributions is not purely quantitative in nature, and that subjective elements enter into the selection of molecules to be used to... 

A more constructive approach to nuclear fusion—one that achieves a controlled release of nuclear energy—is to heat a plasma, or ionized gas, by passing an electric current through it. The very fast ions in the plasma are kept away from the walls of the container with magnetic fields. This method of achieving fusion is the subject of intense research and is beginning to show signs of success (Fig. 17.27). 

Kumar, A. Cocking, E.C. (1987). Protoplast fusion A novel approach to organelle genetics in higher plants. American Journal of Botany, 74, 1289-303. 

Johnsson, N. and Johnsson, K. (2003). A fusion of disciplines chemical approaches to exploit fusion proteins for functional genomics. Chem-biochem 4, 803-810. 

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