Statistical theory of intermittency in a multi-scale model of MHD and micro-turbulence

TL;DR

This paper develops a statistical framework to analyze intermittency in plasma transport by integrating multi-scale effects of MHD and micro-instabilities, addressing the complex interplay of coherent structures and bursty events.

Contribution

It introduces a comprehensive multi-scale model that simultaneously accounts for tearing and micro-instabilities, advancing the understanding of intermittent transport in plasma confinement.

Findings

Derived probability distribution functions for transport events.

Showed the impact of coherent structures on transport intermittency.

Provided a theoretical basis for predicting bursty transport phenomena.

Abstract

Traditionally the effects of MHD instabilities and micro-instabilities on plasma confinement are investigated separately. However, these two instabilities often occur simultaneously, with the overlap of the dynamics on a broad range of spatial scales. It is thus vital to incorporate these instabilities consistently by a proper multi-scale modeling. Furthermore, there has been an overwhelming evidence that the overall transport of heat and particles is significantly influenced by intermittency (or bursty events) caused by coherent structures. A crucial question in plasma confinement is thus the prediction of the probability distribution functions (PDFs) of the transport due to these structures and of their formation. In this paper, we investigate intermittent transport in a multi-scale model by consistently incorporating both tearing instabilities and micro-instability due to pressure gradient.