Flux concentrations in turbulent convection

TL;DR

This paper reports on high-resolution magneto-convection simulations demonstrating flux concentration formation from uniform magnetic fields, with findings suggesting the involvement of negative effective magnetic pressure instability (NEMPI) despite positive pressure regions.

Contribution

It introduces new simulation results showing flux concentrations forming in turbulent convection, challenging previous assumptions about the role of negative magnetic pressure regions.

Findings

Flux concentrations form within ten convective turnover times.

Structures persist close to a turbulent diffusion time.

Formation occurs even where effective magnetic pressure is positive.

Abstract

We present preliminary results from high resolution magneto-convection simulations where we find the formation of flux concentrations from an initially uniform magnetic field. We compute the effective magnetic pressure but find that the concentrations appear also in places where it is positive. The structures appear in roughly ten convective turnover times and live close to a turbulent diffusion time. The time scales are compatible with the negative effective magnetic pressure instability (NEMPI), although structure formation is not restricted to regions where the effective magnetic pressure is negative.