Long-term relaxation of ${1D}$ self-gravitating systems

TL;DR

This paper studies the long-term relaxation of 1D self-gravitating systems using kinetic theory and simulations, confirming theoretical predictions and revealing the impact of collective effects on diffusion.

Contribution

It provides a comprehensive validation of kinetic theory predictions for 1D self-gravitating systems, including the effects of collective phenomena and quasi kinetic blocking.

Findings

Collective effects reduce diffusion by a factor of about 10.

Predicted flux for Plummer equilibrium matches simulation measurements.

All combinations of equilibria and effects agree with Balescu-Lenard and Landau predictions.

Abstract

We investigate the long-term relaxation of one-dimensional (${1D}$) self-gravitating systems, using both kinetic theory and $N$-body simulations. We consider thermal and Plummer equilibria, with and without collective effects. All combinations are found to be in clear agreement with respect to the Balescu-Lenard and Landau predictions for the diffusion coefficients. Interestingly, collective effects reduce the diffusion by a factor ${\sim 10}$. The predicted flux for Plummer equilibrium matches the measured one, which is a remarkable validation of kinetic theory. We also report on a situation of quasi kinetic blocking for the same equilibrium.