Radial orbit instability: review and perspectives

TL;DR

This paper reviews the radial orbit instability in spherical self-gravitating systems, discussing its history, and introduces a symplectic method for stability analysis related to dissipation-induced instabilities in mechanics and plasma physics.

Contribution

It provides a comprehensive overview of radial orbit instability and introduces a symplectic approach for stability analysis, connecting astrophysics with theoretical mechanics.

Findings

The symplectic method offers a new tool for stability analysis.

Historical overview enhances understanding of radial orbit instability.

Connections to dissipation-induced instability mechanisms are established.

Abstract

This paper presents elements about the radial orbit instability, which occurs in spherical self-gravitating systems with a strong anisotropy in the radial velocity direction. It contains an overview on the history of radial orbit instability. We also present the symplectic method we use to explore stability of equilibrium states, directly related to the dissipation induced instability mechanism well known in theoretical mechanics and plasma physics.