When disorder looks like order: a new model to explain radial magnetic fields in young supernova remnants

TL;DR

This paper introduces a 3D model explaining radial magnetic fields in young supernova remnants, proposing that observed patterns may result from CRE distribution effects rather than intrinsic field structure.

Contribution

It presents a novel explanation for radial magnetic fields in SNRs, highlighting the role of CRE distribution and selection effects in observed polarization patterns.

Findings

Quasi-parallel CRE acceleration concentrates electrons in radial field regions.

Disordered magnetic fields can appear ordered due to CRE distribution effects.

Intrinsic radial fields with quasi-perpendicular acceleration resemble observed polarization in SN1006.

Abstract

Radial magnetic fields are observed in all known young, shell-type supernova remnants (SNRs) in our Galaxy, including Cas A, Tycho, Kepler, and SN1006 and yet the nature of these radial fields has not been thoroughly explored. Using a 3D model, we consider the existence and observational implications of an intrinsically radial field. We also present a new explanation of the origin of the radial pattern observed from polarization data as resulting from a selection effect due to the distribution of cosmic-ray electrons (CREs). We show that quasi-parallel acceleration can concentrate CREs at regions where the magnetic field is radial, making a completely turbulent field appear ordered, when it is in fact disordered. We discuss observational properties that may help distinguish between an intrinsically radial magnetic field and the case where it only appears radial due to the CRE distribution. We also show that the case of an intrinsically radial field with a quasi-perpendicular CRE acceleration mechanism has intriguing similarities to the observed polarization properties of SN1006.