Plasma Physics Seminar
Monday, April 16
2535 Engineering Hall
Speaker: Professor Gregory G. Howes, University of Iowa
"Kinetic Turbulence in Space and Astrophysical Plasmas: Theoretical, Numerical, and Experimental Investigations"
Abstract: In many turbulent space and astrophysical plasma environments, the dissipation of the turbulence, and consequent conversion of turbulent fluctuation energy to plasma heat, occurs at scales on which the plasma dynamics is collisionless. Direct access to the near Earth solar wind provides a unique opportunity to confront our understanding of the dynamics of kinetic plasma turbulence, and its dissipation via collisionless damping mechanisms, with in situ spacecraft measurements. Significant effort has recently been focused on employing the gyrokinetic formalism to study the dissipation of turbulence in the solar wind, taking advantage of sophisticated numerical techniques developed for use in the fusion community. Here I will report on some of the most recent successes of this effort, in particular the first three-dimensional, nonlinear gyrokinetic simulation of plasma turbulence resolving scales from the ion to electron gyroradius with a realistic mass ratio, where all damping is provided by resolved physical mechanisms. Complementing this theoretical and numerical research program are experiments on the Large Plasma Device (LAPD) at UCLA to measure the nonlinear interactions between counterpropagating Alfven waves, the fundamental building block of Alfvenic plasma turbulence.