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Plasma Physics Colloquium

Friday, April 5, 2013 - 2:00pm - 3:00pm
Columbia University Morningside Campus 210 Mudd (APAM Conference Room)
Scott Baalrud
Theoretical Division, Los Alamos National Laboratory, and Department of Physics and Astronomy, University of Iowa

"An Effective Potential Theory for Transport Coefficients Across Coupling Regimes"

The microscopic dynamics of Coulomb collisions determines macroscopic transport properties of plasmas such as diffusivity, resistivity, viscosity, etc. Conventional plasma kinetic theories assume that since Coulomb interactions are long range, the momentum transferred in the majority of binary encounters is small. This assumption is used to form an expansion parameter based on the smallness of scattering angles. However, the assumption breaks down in strongly coupled plasmas, where the interaction potential energy is comparable to the particle kinetic energies. These include dense plasmas (inertial confinement fusion, white dwarfs, giant planets, etc.), dusty plasmas and ultracold plasmas. In this talk, a method of extending traditional plasma theories to stronger coupling regimes will be discussed. Like the traditional theories, ours is based on a binary collision picture, but where particles interact via an effective potential that includes average effects of the intervening medium; including both correlations and screening self-consistently. The theory is used to calculate the self-diffusion coefficient in a one-component plasma and the temperature relaxation rate in an electron-ion plasma. The results are compared with experimental measurements and classical molecular dynamics simulations, which show good agreement across coupling regimes. Possible refinements to the theory will also be discussed. This talk is intended for a general physics audience; traditional plasma descriptions will be reviewed before discussing the generalization to strong coupling.

Host: Andrew Cole

Categories: Academic: Lecture