Fusion Science and Technology / Volume 53 / Number 2T / February 2008 / Pages 68-84
Technical Paper / Kinetic Theory
Kinetic theory studies the macroscopic properties of large numbers of particles, starting from their (classical) equations of motion while the thermodynamics describes the equilibrium behavior of macroscopic objects in terms of concepts such as work, heat, and entropy. The phenomenological laws of thermodynamics tell us how these quantities are constrained as a system approaches its equilibrium. At the microscopic level, we know that these systems are composed of particles (atoms, particles), whose interactions and dynamics are reasonably well understood in terms of more fundamental theories. If these microscopic descriptions are complete, we should be able to account for the macroscopic behavior, i.e. derive the laws governing the macroscopic state functions in equilibrium. Kinetic theory attempts to achieve this objective. In particular, we shall try to answer the following questions:
How can we define equilibrium for a system of moving particles?
Do all systems naturally evolve towards an equilibrium state?
What is the time evolution of a system that is not quite in equilibrium?