Machine Learning Characterization of Intermittency in Relativistic Pair Plasma Turbulence: Single and Double Sheet Structures

The physics of turbulence in magnetized plasmas remains an unresolved problem. The most poorly understood aspect is intermittency—spatiotemporal fluctuations superimposed on the self-similar turbulent motions. We employ a novel machine learning analysis technique to segment turbulent flow structures...

Full description

Saved in:
Bibliographic Details
Main Authors: Trung Ha, Joonas Nättilä, Jordy Davelaar, Lorenzo Sironi
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Letters
Subjects:
Online Access:https://doi.org/10.3847/2041-8213/add47b
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The physics of turbulence in magnetized plasmas remains an unresolved problem. The most poorly understood aspect is intermittency—spatiotemporal fluctuations superimposed on the self-similar turbulent motions. We employ a novel machine learning analysis technique to segment turbulent flow structures into distinct clusters based on statistical similarities across multiple physical features. We apply this technique to kinetic simulations of decaying (freely evolving) and driven (forced) turbulence in a strongly magnetized pair-plasma environment, and find that the previously identified intermittent fluctuations consist of two distinct clusters: (i) current sheets, thin slabs of electric current between merging flux ropes, and; (ii) double sheets, pairs of oppositely polarized current slabs, possibly generated by two nonlinearly interacting Alfvén-wave packets. The distinction is crucial for the construction of realistic turbulence subgrid models.
ISSN:2041-8205