We study numerically and theoretically (on a heuristic level) the time evolution of a gas confined to a cube of size L3 divided into two parts by a piston with mass ML ∼ L2 which can only move in the x-direction. Starting with a uniform "double-peaked" (non Maxwellian) distribution of the gas and a stationary piston, we find that (a) after an initial quiescent period the system becomes unstable and the piston performs a damped oscillatory motion, and (b) there is a thermalization of the system leading to a Maxwellian distribution of the gas velocities. The time of the onset of the instability appears to grow like L log L while the relaxation time to the Maxwellian grows like L7/2.
All Science Journal Classification (ASJC) codes
- Statistical and Nonlinear Physics
- Mathematical Physics
- Ideal gas
- Mechanical equilibrium
- Thermodynamical equilibrium