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Abstract
In Part 1 of this thesis, the neoclassical transport in stellarator reactors is studied in detail. It is found that the electron energy confinement time is in general comparable to that of the ions regardless of the size of the machine. Although the neoclassical losses are large, numerical examples show that ignition can be achieved in a reasonably sized machine. The kinetic calculation for the ion transport with the effect of collisionless detrapping/entrapping has not been carried out. This would be a good subject for later investigation.
The energy transfer from thermonuclear (alpha)-particles to the background plasma is calculated in Part 2. It is found that (alpha)-particles can transfer most of their energy into the background plasma before collisionally scatter into the trapping region and are lost.
In Part 3, the convective equilibrium hypothesis is proposed for high (beta) reactors which have regions where the plasma (beta) exceeds the critical (beta). Although the convective transport cannot be calculated precisely, it is shown that the density and temperature profiles in the convective region can still be estimated. A simple mixing-length theory shows that the convective transport is highly efficient. A detailed study of the nonlinear behavior of convective cells is currently being investigated.
A novel power cycle for direct conversion of (alpha)-particle energy into electricity is proposed for an ignited plasma in a stellarator reactor in Part 4. In analyzing the physics of the cycle, there appears to be no major physical or engineering obstacle that would make the cycle impractical. This power cycle may provide an alternative scheme for extracting energy from D-T fueled reactors and may become an important scheme for energy conversion for advanced neutron-lean fueled reactors. By operating two or more reactors in tandem, the cycle can be made self-sustaining. The dynamics of a coupled reactor reactor system will be the subject of a later study and the detailed engineering aspects of the cycle still remain to be investigated.
