ORIGIN OF CORE-HALO STRUCTURE IN ONE-DIMENSIONAL SELF-GRAVITATING SYSTEM

The relaxation process of self-gravitating systems is examined by using one dimensional numerical simulation. We get the asymptotic distribution function which disagrees with that proposed by Lynden-Bell. Our distribution function has two peaks in low and high energy regions and a valley in the medium energy region. This characteristic core-halo structure in phase space has been observed in many simulations, We clarify the dynamical mechanism which generates this 'core-halo' structure. The essence of this mechanism is that the elements of the system are accelerated (or decelerated) very effectively by the evolving gravitational potential in a specific energy region, reflecting the initial conditions.