From Shock to Synchrotron: a mini-review on magnetic turbulence in Supernova Remnants

TL;DR

This mini-review discusses recent advances in understanding magnetic turbulence in Supernova Remnants through X-ray polarization measurements by IXPE, highlighting implications for particle acceleration and magnetic field structure.

Contribution

It summarizes key observational results from IXPE on SNRs and discusses how polarization data combined with spectral analysis enhances understanding of magnetic turbulence.

Findings

IXPE provides new polarization data revealing magnetic field geometry.

Polarization measurements help constrain magnetic turbulence scales.

Results improve understanding of particle acceleration in SNRs.

Abstract

Magnetic turbulence plays a crucial role in confining charged particles near the shock front of Supernova Remnants, enabling them to reach energies up to hundreds of TeV through a process known as Diffusive Shock Acceleration (DSA). These high-energy electrons spiral along magnetic field lines, emitting X-ray synchrotron radiation. The launch of the Imaging X-ray Polarimetry Explorer (IXPE) has opened a new window into the study of magnetic fields in SNRs through X-ray polarization measurements. For the first time, IXPE allows us to resolve the polarization degree (PD) and angle (PA) in the X-ray band across different areas of SNRs, offering direct insight into the geometry and coherence of magnetic fields on different scales. In this mini-review, I summarize the key observational results on SNRs obtained with IXPE over the past four years and discuss their implications for our understanding of magnetic turbulence in synchrotron-emitting regions. I also show how we can combine polarization parameters and standard X-ray spectral/imaging analysis to better constrain the structure and scale of magnetic turbulence immediately downstream of the shock and understand the particle acceleration occurring in SNRs.