PARTICLE DIFFUSION ACCELERATION IN SPATIALLY PERIODIC STRUCTURES EXPOSED TO RECTANGULAR TIME-PERIODIC FIELDS

• Published in: East European journal of physics 2015-11, Vol.2 (3), p.55-63
• Main Authors: I. G. Marchenko, I. I. Marchenko
• Format: Article
• Language: eng ; ukr
• ISSN: 2312-4334; 2312-4539

This scientific paper studies the abnormal diffusion of particles in spatially periodic structures exposed to the action of time –periodic rectangular fields. A choice of such a type of the field is related to the need of finding out physical reasons for an increase in the diffusion coefficient at different field amplitudes. As for the impact on the diffusion coefficient the entire eventual amplitude range was divided into three domains whose functional behavior of the diffusion coefficient differs with a change in temperature. It has been shown that the maximum increase in the diffusion can be reached only in the narrow amplitude range of the external periodic force defined by system dissipative properties. This range shows abnormal temperature relationship of the diffusion coefficient, in particular its exponential growth with a drop in temperature. A physical reason for such an abnormal increase in diffusion can be the availability of two populations of particles: “localized” and “running”. An optimal choice of the amplitude of the external field provides long jumps of running particles in comparison with localized ones. The amplification ratio of the diffusion can significantly be changed through the variation of the frequency and amplitude of the external field. This offers the challenge for new technological applications of studied effects.