Escape and transport in chaotic motion of charged particles in a magnetized plasma under the influence of two and three modes of drift waves

TL;DR

This paper explores how multi-wave drift wave interactions influence particle escape and transport in tokamak plasmas, revealing that adding waves increases chaos and affects confinement strategies.

Contribution

It introduces a Hamiltonian model analyzing multi-wave effects on particle dynamics, highlighting how a third wave alters escape patterns and transport regimes in plasma confinement.

Findings

Adding a third wave increases basin entropy and escape rates.

Resonant scattering disrupts coherent transport pathways.

Transition from anomalous to normal diffusion with wave number changes.

Abstract

This study investigates how two- and three-wave configurations govern particle escape and transport in tokamak edge plasmas. Using a Hamiltonian model derived from drift-wave turbulence, we analyze test particle dynamics through Poincar\'e maps, fractal escape basins, and entropy metrics. Introducing a third wave increases basin entropy, enhancing particle escape rates while reducing basin boundary entropy, indicative of suppressed basin mixing. Escape time analyses reveal resonant scattering disrupts coherent transport pathways, linking fractal absorption patterns to heat load mitigation in divertors. Characteristic transport is also analyzed and regimes transition between anomalous $(\alpha > 1)$ and normal diffusion $(\alpha \approx 1)$, two-wave systems sustain anomalous transport, while the third wave homogenizes fluxes through stochastic scattering. Fractal structures in escape basins and entropy-driven uncertainty quantification suggest strategies to engineer transport properties, balancing chaos and order for optimized confinement.