Sticky islands in stochastic webs and anomalous chaotic cross-field particle transport by ExB electron drift instability

TL;DR

This paper investigates how the ExB electron drift instability causes chaotic particle motion and super-diffusive transport in plasma, revealing the role of phase space islands and sticking times in anomalous transport behavior.

Contribution

It introduces a scaling exponent to characterize phase space transport and demonstrates the impact of island sticking times on super-diffusive regimes in plasma particle dynamics.

Findings

Transport is super-diffusive due to sticking to phase space islands.

Sticking times follow power-law statistics, influencing transport regimes.

Different island types lead to multiple super-diffusive regimes.

Abstract

The ExB electron drift instability, present in many plasma devices, is an important agent in cross-field particle transport. In presence of a resulting low frequency electrostatic wave, the motion of a charged particle becomes chaotic and generates a stochastic web in phase space. We define a scaling exponent to characterise transport in phase space and we show that the transport is anomalous, of super-diffusive type. Given the values of the model parameters, the trajectories stick to different kinds of islands in phase space, and their different sticking time power-law statistics generate successive regimes of the super-diffusive transport.