Chaotic escape of impurities and sticky orbits in toroidal plasmas

Author(s)

Souza, L. C. ; Sales, M. R. ; Mugnaine, M. ; Szezech, J. D. ; Caldas, I. L. ; Viana, R. L.

• Document type: Journal article
• Source: PHYSICAL REVIEW E; v. 109, n. 1, p. 10-pg., 2024-01-05.

Abstract

We investigate chaotic impurity transport in toroidal fusion plasmas (tokamaks) from the point of view of passive advection of charged particles due to E x 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 Poincare 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. (AU)

• FAPESP's process: 22/04251-7 - Fractal Structures in Plasma Physics
• Grantee: Iberê Luiz Caldas
• Support Opportunities: Research Grants - Visiting Researcher Grant - Brazil
• FAPESP's process: 18/03211-6 - Non linear dynamics
• Grantee: Iberê Luiz Caldas
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 22/12736-0 - Oscillations in magnetically confined plasmas
• Grantee: Michele Mugnaine
• Support Opportunities: Scholarships in Brazil - Post-Doctoral