Souza L C, Sales M R, Mugnaine M, Szezech J D, Caldas I L, Viana R L
Universidade Federal do Paraná, Departamento de Física, Curitiba, PR 81531-990, Brazil.
Universidade Estadual de Ponta Grossa, Programa de Pós-Graduação em Ciências, Ponta Grossa, PR 84030-900, Brazil.
Phys Rev E. 2024 Jan;109(1-2):015202. doi: 10.1103/PhysRevE.109.015202.
We investigate chaotic impurity transport in toroidal fusion plasmas (tokamaks) from the point of view of passive advection of charged particles due to E×B drift motion. We use realistic tokamak profiles for electric and magnetic fields as well as toroidal rotation effects, and consider also the effects of electrostatic fluctuations due to drift instabilities on particle motion. A time-dependent one degree-of-freedom Hamiltonian system is obtained and numerically investigated through a symplectic map in a Poincaré surface of section. We show that the chaotic transport in the outer plasma region is influenced by fractal structures that are described in topological and metric point of views. Moreover, the existence of a hierarchical structure of islands-around-islands, where the particles experience the stickiness effect, is demonstrated using a recurrence-based approach.
我们从带电粒子因E×B漂移运动而产生的被动平流角度，研究环形聚变等离子体（托卡马克）中的混沌杂质输运。我们使用了实际的托卡马克电场和磁场分布以及环形旋转效应，还考虑了漂移不稳定性引起的静电涨落对粒子运动的影响。通过在庞加莱截面中使用辛映射，得到了一个含时的单自由度哈密顿系统并进行了数值研究。我们表明，外等离子体区域的混沌输运受到从拓扑和度量角度描述的分形结构的影响。此外，使用基于递归的方法证明了存在岛中岛的层次结构，粒子在其中会经历黏滞效应。
