Radiative Magnetic Reconnection in Astrophysics

TL;DR

Radiative magnetic reconnection is a rapidly advancing field in high-energy astrophysics, focusing on how radiation influences magnetic reconnection processes and their observable signatures in various astrophysical systems.

Contribution

This review introduces the concept of radiative magnetic reconnection, emphasizing the need to incorporate radiation effects into reconnection theory and modeling for better astrophysical understanding.

Findings

Radiation reaction limits particle acceleration.

Radiative cooling and resistivity significantly affect reconnection dynamics.

Radiative reconnection explains phenomena in pulsar wind nebulae, black hole systems, and gamma-ray bursts.

Abstract

I review a new rapidly growing area of high-energy plasma astrophysics --- radiative magnetic reconnection, i.e., a reconnection regime where radiation reaction influences reconnection dynamics, energetics, and nonthermal particle acceleration. This influence be may be manifested via a number of astrophysically important radiative effects, such as radiation-reaction limits on particle acceleration, radiative cooling, radiative resistivity, braking of reconnection outflows by radiation drag, radiation pressure, viscosity, and even pair creation at highest energy densities. Self-consistent inclusion of these effects in magnetic reconnection theory and modeling calls for serious modifications to our overall theoretical approach to the problem. In addition, prompt reconnection-powered radiation often represents our only observational diagnostic tool for studying remote astrophysical systems; this underscores the importance of developing predictive modeling capabilities to connect the underlying physical conditions in a reconnecting system to observable radiative signatures. This Chapter gives an overview of recent theoretical progress in developing basic physical understanding of radiative reconnection, with a special emphasis on astrophysically important radiation mechanisms like synchrotron, curvature, and inverse-Compton. It also offers a broad review of key high-energy astrophysical applications of radiative reconnection, such as: pulsar wind nebulae and magnetospheres, accreting black-hole coronae and jets in XRBs and AGN, magnetospheres of magnetars, and Gamma-Ray Bursts. Finally, this Chapter discusses the most critical open questions and outlines the directions for future research in this exciting new frontier of plasma astrophysics.