Simulation of the collapse and dissipation of Langmuir wave packets

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859385· OSTI ID:6310977

Newman, D L; Winglee, R M; Robinson, P A; Glanz, J; Goldman, M V ^[1]

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1. Department of Astrophysical, Planetary, and Atmospheric Sciences, University of Colorado at Boulder, Boulder, Colorado 80309 (USA)

The collapse of isolated Langmuir wave packets is studied numerically in two dimensions using both particle-in-cell (PIC) simulations and by integrating the Zakharov partial differential equations (PDE's). The initial state consists of a localized Langmuir wave packet in an ion background that either is uniform or has a profile representative of the density wells in which wave packets form during strong plasma turbulence. Collapse thresholds are determined numerically and compared to analytical estimates. A model in which Langmuir damping is significantly stronger than Landau damping is constructed which, when included in the PDE simulations, yields good agreement with the collapse dynamics observed in PIC simulations for wave packets with initial wave energy densities small compared to the thermal level. For more intense initial Langmuir fields, collapse is arrested in PIC simulations at lower field strengths than in PDE simulations. Neither nonlinear saturation of the density perturbation nor fluid electron nonlinearities can account for the difference between simulation methods in this regime. However, at these wave levels inhomogeneous electron heating and coherent jets of transit-time accelerated electrons in phase space are observed, resulting in further enhancement of wave damping and the consequent reduction of fields in the PIC simulations.

• OSTI ID: 6310977
• Journal Information: Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 2:11; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700103 -- Fusion Energy-- Plasma Research-- Kinetics
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
ACCELERATION
ANNIHILATION
BASIC INTERACTIONS
BURNOUT
CORRELATIONS
DAMPING
DIFFERENTIAL EQUATIONS
ELECTROMAGNETIC INTERACTIONS
ELECTRON TEMPERATURE
ELECTRONS
ELEMENTARY PARTICLES
ENERGY
ENERGY LOSSES
EQUATIONS
FERMIONS
INHOMOGENEOUS PLASMA
INTERACTIONS
LANDAU DAMPING
LEPTONS
LOSSES
MATHEMATICAL SPACE
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
PARTIAL DIFFERENTIAL EQUATIONS
PHASE SPACE
PLASMA
PLASMA SIMULATION
PLASMA WAVES
SIMULATION
SPACE
THRESHOLD ENERGY
TURBULENCE
TWO-DIMENSIONAL CALCULATIONS
WAVE PACKETS