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Whistler turbulence forward cascade: Three‐dimensional particle‐in‐cell simulations
Author(s) -
Chang Ouliang,
Peter Gary S.,
Wang Joseph
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl049827
Subject(s) - physics , whistler , turbulence , computational physics , cascade , energy cascade , isotropy , wavelength , anisotropy , particle in cell , magnetic field , wavenumber , perpendicular , electron , optics , mechanics , geometry , quantum mechanics , mathematics , chemistry , chromatography
The first fully three‐dimensional particle‐in‐cell (PIC) simulation of whistler turbulence in a magnetized, homogeneous, collisionless plasma has been carried out. An initial relatively isotropic spectrum of long‐wavelength whistlers is imposed upon the system, with an initial electron β = 0.10. As in previous two‐dimensional simulations of whistler turbulence, the three‐dimensional system exhibits a forward cascade to shorter wavelengths and broadband, turbulent spectra with a wave vector anisotropy in the sense of stronger fluctuation energy at k ⊥ than at comparable k ∥ where the respective subscripts represent directions perpendicular and parallel to the background magnetic field B o . However, the three‐dimensional (3D) simulations display quantitative differences with comparable two‐dimensional (2D) computations. In the 3D runs, turbulence develops a stronger anisotropic cascade more rapidly than in 2D runs. Furthermore, reduced magnetic fluctuation spectra in 3D runs are less steep functions of perpendicular wave numbers than those from 2D simulations. The much larger volume of perpendicular wave vector space in 3D appears to facilitate the transfer of fluctuation energy toward perpendicular directions.