Smoothed Particle Hydrodynamics in Astrophysics

TL;DR

This review explains how Smoothed Particle Hydrodynamics (SPH) is used in astrophysics, highlighting its advantages in simulating complex, high dynamic range gas dynamics with conservation properties and adaptability.

Contribution

It provides a comprehensive overview of the modern formulation, extensions, and applications of SPH in astrophysics, including critical discussions on its accuracy and convergence.

Findings

SPH effectively models inviscid gas dynamics in astrophysics.

Extensions of SPH incorporate physics like radiative transfer and magnetic fields.

SPH's convergence properties vary with problem type.

Abstract

This review discusses Smoothed Particle Hydrodynamics (SPH) in the astrophysical context, with a focus on inviscid gas dynamics. The particle-based SPH technique allows an intuitive and simple formulation of hydrodynamics that has excellent conservation properties and can be coupled to self-gravity easily and highly accurately. The Lagrangian character of SPH allows it to automatically adjust its resolution to the clumping of matter, a property that makes the scheme ideal for many applications in astrophysics, where often a large dynamic range in density is encountered. We discuss the derivation of the basic SPH equations in their modern formulation, and give an overview about extensions of SPH developed to treat physics such as radiative transfer, thermal conduction, relativistic dynamics or magnetic fields. We also briefly describe some of the most important applications areas of SPH in astrophysical research. Finally, we provide a critical discussion of the accuracy of SPH for different hydrodynamical problems, including measurements of its convergence rate for important classes of problems.