Observation of self-binding turbulent fluctuations in simulation plasma and their relevance to plasma kinetic theories

Journal Article · Thu Sep 01 00:00:00 EDT 1983 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.864429· OSTI ID:5881467

Berman, R H; Tetreault, D J; Dupree, T H

Non-wave-like fluctuations of the phase-space density are observed in simulations of turbulent plasma. During decay from an initial state, the mean square fluctuation level decays at a much slower rate than that of an individual fluctuation. The distribution function of the fluctuation amplitudes becomes non-Gaussian (skewed) in favor of negative fluctuations. An enhancement in the aggregate fluctuation lifetime is also observed when the turbulence is driven by an external source. A model based on a collection of self-binding negative fluctuations, called phase-space density holes, can explain the observations. Collisions between holes produce hole fragments and lead to fluctuation decay. However, the hole fragments are self-binding and tend to recombine into new holes. The implications of these results for kinetic theories of plasma turbulence are discussed. In particular, it is shown that the theory of clumps, when suitably modified to include fluctuation self-binding, can explain many features of the nonlinear instability recently observed in computer simulations.

• Research Organization: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
• OSTI ID: 5881467
• Journal Information: Phys. Fluids; (United States), Vol. 26:9
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA
FLUCTUATIONS
TURBULENCE
DISTRIBUTION FUNCTIONS
ELECTRON COLLISIONS
HOLES
KINETIC EQUATIONS
LIFETIME
PHASE SPACE
PLASMA DENSITY
PLASMA SIMULATION
COLLISIONS
EQUATIONS
FUNCTIONS
MATHEMATICAL SPACE
SIMULATION
SPACE
VARIATIONS
700105* - Fusion Energy- Plasma Research- Plasma Kinetics-Theoretical- (-1987)