Dynamic characteristics of alpha-particle heating based upon the Fokker-Planck equation in D-T fusion reactor core plasmas

The paper presents an extension of previous work on α-particle heated D-T reactor-core plasma, in which the effect of energy relaxation of α-particles (in the presence of α-particle loss) is included in a more precise manner on the basis of the Fokker-Planck equation. Two basic problems are treated in this paper: (1) the ''start-up'' or ''ignition'' problem by means of neutral-beam injection heating, and (2) the determination of α-particle energy transfer function for linear perturbations and the calculation of the growth rate of ''thermal instability''. Particular emphasis is laid on the discrepancies between the results of our model and those of the ''instantaneous-heating model'' proposed hitherto by many authors. It is found that an ''inertial'' property inherent in the energy distribution function of α-particles as well as a sort of ''negative feedback'' in the energy transfer to background electrons lead to pronounced effects on dynamics and control of α-particle-heated D-T reactors. (author)