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DY: Fachverband Dynamik und Statistische Physik

DY 22: Statistical Physics (general)

DY 22.6: Invited Talk

Wednesday, March 13, 2013, 16:30–17:00, H48

Entropy based approaches to transport — •Thomas Christen — ABB Corporate Research, CH-5405 Baden, Schweiz

The quasi-stationary distribution function for a gas of independent particles, which are not in local thermal equilibrium (LTE) but strongly interact with an LTE medium, can often be described by a linear Boltzmann transport equation (BTE). In order to make use of a truncated expansion of the distribution function in terms of moments that satisfy generalized hydrodynamic equations, an appropriate closure method is required. An often used closure method is based on constrained entropy maximization. We show that a closure based on constrained entropy production minimization is superior to entropy maximization, and mitigates some well-known errors of the latter. As an example, we discuss non-LTE radiation in an LTE-plasma and show how average heat transport coefficients can be determined for realistic absorption spectra. As a second example, we illustrate the approach for electric conduction in low-dimensional structures.