2:00 PM–5:00 PM, Monday, November 12, 2007
Rosen Centre Hotel - Junior Ballroom
Chair: Fred Skiff, University of Iowa
Abstract ID: BAPS.2007.DPP.CI1.1
2:00 PM–2:30 PM
Ryan Lindberg
(University of California, Berkeley)
We present a model of kinetic effects in Langmuir wave dynamics using a nonlinear distribution function that includes particle separatrix crossing and self-consistent electrostatic evolution. This model is based on the adiabatic motion of the particles in the wave, and uses the fundamental frequency, its harmonics, and a nearly uniform electric field to describe BGK-type Langmuir waves over a wide range of temperatures ($0.1 \le k\lambda_D \le 0.4$). This asymptotic distribution function yields a nonlinear frequency shift of the Langmuir wave that agrees well with Vlasov simulations, and can furthermore be used to determine the electrostatic energy required to develop the phase-mixed, asymptotic state. Energy conservation is used in conjunction with our kinetic theory results to build a simplified model of nonlinear Landau-type damping. The resulting nonlinear, dynamic frequency shift and damping can be used in an extended three-wave type model of driven Langmuir waves, and we discuss comparisons of this model to Vlasov simulations in the context of Raman backscatter.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.DPP.CI1.1