Ideal Magnetohydrodynamics with Radiative Terms: Energy Conditions

TL;DR

This paper derives energy conditions for a perfect fluid influenced by magnetic and radiation fields, crucial for understanding astrophysical phenomena like neutron stars and accretion processes.

Contribution

It introduces energy conditions for a magnetized, radiative perfect fluid in the optically thick regime, extending previous models to include radiation effects.

Findings

Energy conditions for magnetized fluids with radiation are formulated.

Conditions reduce to known magnetized fluid cases when radiation is zero.

Framework applicable to astrophysical scenarios involving strong magnetic and radiation fields.

Abstract

Nowadays, the magnetic and radiation fields are very important to understand the matter accretion into compact objects, the dynamics of binary systems, the equilibrium configurations of neutron stars, the photon diffusion, etc. The energy and the momentum associated to these fields, along with the matter one, need to satisfy some conditions that guarantee an appropriate physical behavior of the source and its gravitational field. Based on this fact, we present the energy conditions for a perfect fluid with magnetic and radiation field, in which the radiation part of the energy-momentum tensor is assumed to be approximately isotropic, in accordance with the optically thick regime. In order to find these conditions, the stress tensor of the system is written in an orthonormal basis in which it becomes diagonal, and the energy conditions are computed through contractions of the energy-momentum tensor with the four velocity vector of an arbitrary observer. Finally, the conditions for a magnetized fluid are presented as a particular case in which the radiation contribution is zero.