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Physical Sciences and Mathematics Commons

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Full-Text Articles in Physical Sciences and Mathematics

Hydrodynamic Relaxation Of An Electron Plasma To A Near-Maximum Entropy State, D. J. Rodgers, S. Servidio, W. H. Matthaeus, D. C. Montgomery, T. B. Mitchell, T. Aziz Jun 2009

Hydrodynamic Relaxation Of An Electron Plasma To A Near-Maximum Entropy State, D. J. Rodgers, S. Servidio, W. H. Matthaeus, D. C. Montgomery, T. B. Mitchell, T. Aziz

Dartmouth Scholarship

Dynamical relaxation of a pure electron plasma in a Malmberg-Penning trap is studied, comparing experiments, numerical simulations and statistical theories of weakly dissipative two-dimensional (2D) turbulence. Simulations confirm that the dynamics are approximated well by a 2D hydrodynamic model. Statistical analysis favors a theoretical picture of relaxation to a near-maximum entropy state with constrained energy, circulation, and angular momentum. This provides evidence that 2D electron fluid relaxation in a turbulent regime is governed by principles of maximum entropy.


Measurement And Simulation Of Laser-Induced Fluorescence From Nonequilibrium Ultracold Neutral Plasmas, A. Denning, Scott D. Bergeson, F. Robicheaux Jan 2009

Measurement And Simulation Of Laser-Induced Fluorescence From Nonequilibrium Ultracold Neutral Plasmas, A. Denning, Scott D. Bergeson, F. Robicheaux

Faculty Publications

We report measurements and simulations of laser-induced fluorescence in ultracold neutral plasmas. We focus on the earliest times, when the plasma equilibrium is evolving and before the plasma expands. In the simulation, the ions interact via the Yukawa potential in a small cell with wrapped boundary conditions. We solve the optical Bloch equation for each ion in the simulation as a function of time. Both the simulation and experiment show the initial increase in ion fluorescence, disorder-induced heating, and coherent oscillation of the rms ion velocity. Detailed modeling of the fluorescence signal makes it possible to use fluorescence spectroscopy to …