ENERGY DISSIPATION and LANDAU DAMPING in TWO- and THREE-DIMENSIONAL PLASMA TURBULENCE

Tak Chu Li, Gregory G. Howes, Kristopher G. Klein, Jason M. TenBarge

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Plasma turbulence is ubiquitous in space and astrophysical plasmas, playing an important role in plasma energization, but the physical mechanisms leading to dissipation of the turbulent energy remain to be definitively identified. Kinetic simulations in two dimensions (2D) have been extensively used to study the dissipation process. How the limitation to 2D affects energy dissipation remains unclear. This work provides a model of comparison between two- and three-dimensional (3D) plasma turbulence using gyrokinetic simulations; it also explores the dynamics of distribution functions during the dissipation process. It is found that both 2D and 3D nonlinear gyrokinetic simulations of a low-beta plasma generate electron velocity-space structures with the same characteristics as that of the linear Landau damping of Alfvén waves in a 3D linear simulation. The continual occurrence of the velocity-space structures throughout the turbulence simulations suggests that the action of Landau damping may be responsible for the turbulent energy transfer to electrons in both 2D and 3D, and makes possible the subsequent irreversible heating of the plasma through collisional smoothing of the velocity-space fluctuations. Although, in the 2D case where variation along the equilibrium magnetic field is absent, it may be expected that Landau damping is not possible, a common trigonometric factor appears in the 2D resonant denominator, leaving the resonance condition unchanged from the 3D case. The evolution of the 2D and 3D cases is qualitatively similar. However, quantitatively, the nonlinear energy cascade and subsequent dissipation is significantly slower in the 2D case.

Original languageEnglish (US)
Article numberL24
JournalAstrophysical Journal Letters
Volume832
Issue number2
DOIs
StatePublished - Jan 12 2016
Externally publishedYes

Keywords

  • plasma
  • turbulence
  • waves

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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