Magnetic fields from Multiplicative Chaos

TL;DR

This paper extends a stochastic multiplicative chaos model to magnetohydrodynamic turbulence, providing a physically motivated framework for modeling coupled velocity and magnetic fields with parameters useful for astrophysical data analysis.

Contribution

It introduces three new models for MHD turbulence based on multiplicative chaos, linking turbulence properties with magnetic fields and offering tools for observational data characterization.

Findings

Models replicate energy cascade and intermittency in MHD turbulence.

Provides parameterized descriptions useful for astrophysical observations.

Extends multiplicative chaos framework to coupled velocity and magnetic fields.

Abstract

An analytical model for fully developed three-dimensional incompressible turbulence was recently proposed in the hydrodynamics community, based on the concept of multiplicative chaos. It consists of a random field represented by means of a stochastic integral, which, with only a few parameters, shares many properties with experimental and numerical turbulence, including in particular energy transfer through scales (the cascade) and intermittency (non-Gaussianity) which is most conveniently controlled with a single parameter. Here, we propose three models extending this approach to MHD turbulence. Our formulae provide physically motivated 3D models of a turbulent velocity field and magnetic field coupled together. Besides its theoretical value, this work is meant to provide a tool for observers: a dozen of physically meaningful free parameters enter the description, which is useful to characterize astrophysical data.