2003/02/27 by I. Ispolatov, Yaroslav Ispolatov, Mikko Karttunen +1 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Canonical ensemble #Classical mechanics #Halo #Instability #Marine and environmental studies #Mean field theory #Mechanics #Metastability #Microcanonical ensemble #Monte Carlo method #Physics #Quantum mechanics #Statistical Mechanics and Entropy #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreve.68.036117
published as Phys.Rev. E68 (2003) 036117 · 9 pages, 14 figures
arxiv created 2003/02/27 · openalex publication_date 2003/09/19 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Collapse and explosion (reverse to collapse) transitions in self-gravitating systems are studied by molecular dynamics simulations. A microcanonical ensemble of point particles confined to a spherical box is considered. The particles interact via an attractive soft Coulomb potential. It is observed that a collapse indeed takes place when the energy of the uniform state is set near or below the metastability-instability threshold (collapse energy) as predicted by the mean-field theory. Similarly, an explosion occurs when the energy of the core-halo state is increased above the explosion energy, where according to the mean-field predictions the core-halo state becomes unstable. For systems consisting of 125-500 particles, the collapse takes about 10(5) single-particle crossing times to complete, while a typical explosion is by an order of magnitude faster. A finite lifetime of metastable states is observed. It is also found that the mean-field description of the uniform and core-halo states is exact within the statistical uncertainty of the molecular dynamics data.