Simulation of the loss-cone instability in spherical systems. I. Dominating harmonic potential

TL;DR

This paper confirms the existence of a gravitational loss-cone instability in spherical stellar systems with a harmonic potential through N-body simulations, revealing its impact on particle diffusion and system stability.

Contribution

It extends previous linear theory by using N-body simulations to analyze the loss-cone instability in harmonic potential systems, showing its effects beyond linear predictions.

Findings

The instability accelerates phase space diffusion.

No significant change in spherical geometry during instability.

Early saturation of the instability observed.

Abstract

A new so-called `gravitational loss-cone instability' in stellar systems has recently been investigated theoretically in the framework of linear perturbation theory and proved to be potentially important in understanding the physical processes in centres of galaxies, star clusters, and the Oort comet cloud. Using N-body simulations of a toy model, we confirm previous findings for the harmonic dominating potential and go beyond the linear theory. Unlike the well-known instabilities, the new one shows no notable change in the spherical geometry of the cluster, but it significantly accelerates the speed of diffusion of particles in phase space leading to an early instability saturation.