Electron magnetohydrodynamic turbulence: universal features
Kavli Institute of Theoretical Physics, University of California, Santa Barbara, CA 93106, USA
Permanent address: University of Central Florida, Orlando, FL 32816-1364, USA.
b e-mail: email@example.com
Received: 1 October 2014
Received in final form: 12 January 2015
Published online: 24 February 2015
The energy cascade of electron magnetohydrodynamic (EMHD) turbulence is considered. Fractal and multi-fractal models for the energy dissipation field are used to determine the spatial intermittency corrections to the scaling behavior in the high-wavenumber (electron hydrodynamic limit) and low-wavenumber (magnetization limit) asymptotic regimes of the inertial range. Extrapolation of the multi-fractal scaling down to the dissipative microscales confirms in these asymptotic regimes a dissipative anomaly previously indicated by the numerical simulations of EMHD turbulence. Several basic features of the EMHD turbulent system are found to be universal which seem to transcend the existence of the characteristic length scale de (which is the electron skin depth) in the EMHD problem: equipartition spectrum; Reynolds-number scaling of the dissipative microscales; scaling of the probability distribution function (PDF) of the electron-flow velocity (or magnetic field) gradient (even with intermittency corrections); dissipative anomaly; and critical exponent scaling.
Key words: Plasma Physics
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2015