The transport coefficients of a 3D (in constants-of-motion space) Fokker–Planck equation are analytically derived for fast ions confined in tokamaks with strong toroidal field (TF) ripples. The expressions obtained allow for a quantitative evaluation of collisional fast ion transport depending on the TF ripple magnitude, on magnetic configuration parameters, on ion energy and the magnetic moment as well as on ion collision rates.
The nature and topological distribution of optical centers within various regions of hot pressed disks of transparent magnesium aluminates spinel ceramics doped with LiF were studied. In the optical absorption spectra of this type of ceramic, bands were revealed at 4.75 eV and 5.3 eV, which were identified with F + -and F-centers, respectively. Because both bands are formed by anionic vacancies which captured one or two electrons, the topological distribution of anionic vacancies was determined. The band at 5.65 eV was also found which is tentatively identified with complex centers of anionic vacancies that capture fluorine ions and electrons. Using X-ray irradiation the variety of absorption bands of hole centers related to cationic vacancies was established. The spatial distribution of cationic vacancies within the ceramic disk was also determined.
Possible fusion reactivity enhancement due to 3 He minority ICRF heating in D-3 He toroidal plasma is demonstrated in present numerical simulations. On this purpose the particle code based on test-particle approach is developed. This code solves guiding center equations for 3 He ions in toroidal magnetic field including Coulomb collisions of these ions with the background deuterons and electrons. A simple Monte Carlo model for ICRF heating is implemented in this code as well. The transformation of 3 He distribution function from Maxwellian to non-Maxwellian due to heating plays the key role for reactivity enhancement. The formation of significant energetic tail gives rise to the reactivity enhancement. This is an important issue for the performance of fusion reactors with minority heating of ICRF.
The investigations of radio-luminescence (RL) in magnesium aluminates spinel crystals at variation of the time, intensity of X-irradiation and temperature of sample were provided. There were registered three prominent RL bands related to electron-hole recombination process at anti-site defects, emission of Mn2+-ions and emission of Cr3+-ions. The kinetics of the growth of indicated RL emissions show the competing processes of the capture of free charge carriers generated at irradiation by intrinsic defects and impurity ions.
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