Whistler turbulence: Particle-in-cell simulations
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Institute of Geophysics and Extraterrestrial Physics, Technical University of Braunschweig, D-38106, Braunschweig (Germany)
Two-dimensional electromagnetic particle-in-cell simulations in a magnetized, homogeneous, collisionless electron-proton plasma demonstrate the forward cascade of whistler turbulence. The simulations represent decaying turbulence, in which an initial, narrowband spectrum of fluctuations at wavenumbers kc/{omega}{sub e}{approx_equal}0.1 cascades toward increased damping at kc/{omega}{sub e}{approx_equal}1.0, where c/{omega}{sub e} is the electron inertial length. The turbulence displays magnetic energy spectra that are relatively steep functions of wavenumber and are anisotropic with more energy in directions relatively perpendicular to the background magnetic field B{sub o}=xB{sub o} than at the same wavenumbers parallel to B{sub o}. In the weak turbulence regime, the primary new results of the simulations are as follows: (1) Magnetic spectra of the cascading fluctuations become more anisotropic with increasing fluctuation energy; (2) the wavevector dependence of the three magnetic energy ratios, |{delta}B{sub j}|{sup 2}/|{delta}B|{sup 2} with j=x,y,z, show good agreement with linear dispersion theory for whistler fluctuations; (3) the magnetic compressibility summed over the cascading modes satisfies 0.3(less-or-similar sign)|{delta}B{sub x}|{sup 2}/|{delta}B|{sup 2}(less-or-similar sign)0.6; and (4) the turbulence heats electrons in directions both parallel and perpendicular to B{sub o}, with stronger heating in the parallel direction.
- OSTI ID:
- 21254530
- Journal Information:
- Physics of Plasmas, Vol. 15, Issue 10; Other Information: DOI: 10.1063/1.2997339; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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