2018/01/15 by Yuta Ito, Ito, Yuta
Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Statistical Mechanics and Entropy #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.1801.04903
openalex publication_date 2018/01/15 · openalex created_date 2018/05/17 · openalex updated_date 2026/07/28
Fundamental relaxation processes in the secular evolution of a collisional star cluster of N-'point' stars have been conventionally discussed based on either of collision kinetic theory (for strong two-body encounters) and wave one (for statistical acceleration and gravitational polarization). If combining the both theories together, one must introduce a self-consistent 'truncated' Newtonian mean-field (m.f.) acceleration of star at position r and time t due to a phase-space distribution function f(r', p',t) for stars A\triangle(r,t)=-Gm(1-(1)/(N))∫| r-r' | > \triangle\fracr-r'| r-r' |3 f(r',p',t)d3r'd3p', where G is the gravitational constant and m the mass of stars. The lower limit \triangle of the distance between two stars is order of the Landau distance. The truncated m.f. acceleration is a necessary consequence due to the strong encounters and m.f. acceleration being not able to 'coexist' at specific distance between stars. The present paper aims at initiating a star-cluster convergent kinetic theory to self-consistently derive kinetic equations of star clusters, mathematically non-divergent in distance- and wavenumber- spaces based on the truncated m.f. acceleration, correct at time scales of the secular evolution. This will be achieved by focusing on mathematical formulations of the Kandrup's generalised-Landau equation including the effect of the strong encounters and by extending the Grad's truncated distribution function and Klimontovich's theory of non-ideal systems.