On Generation of magnetic field in astrophysical bodies

TL;DR

This paper uses a field-theoretic approach to analyze energy transfer in MHD turbulence, revealing a significant transfer from large-scale velocity to magnetic fields, explaining large-scale magnetic energy growth without linear approximations.

Contribution

It introduces a non-linear field-theoretic calculation showing large-scale magnetic energy growth driven by energy transfer from velocity fields, without relying on linear dynamo models.

Findings

Large energy transfer from velocity to magnetic field in MHD turbulence

Growth of large-scale magnetic energy primarily due to this transfer

No linear approximation like alpha-dynamo used in analysis

Abstract

In this letter we compute energy transfer rates from velocity field to magnetic field in MHD turbulence using field-theoretic method. The striking result of our field theoretic calculation is that there is a large energy transfer rate from the large-scale velocity field to the large-scale magnetic field. We claim that the growth of large-scale magnetic energy is primarily due to this transfer. We reached the above conclusion without any linear approximation like that in $\alpha$-dynamo.