Ann. Geophys., 26, 543-553, 2008
www.ann-geophys.net/26/543/2008/
© European Geosciences Union 2008
Large-scale simulations of 2-D fully kinetic Farley-Buneman turbulence
M. M. Oppenheim1, Y. Dimant1, and L. P. Dyrud2
1Center for Space Physics, Boston University, USA
2Center for Remote Sensing, Fairfax, VA, USA
Abstract. Currents flowing in the Earth's ionospheric electrojets often
develop Farley-Buneman (FB) streaming instabilities and become
turbulent. The resulting electron density irregularities cause
these regions to readily scatter VHF and UHF radar
signals. Many of the observed characteristics of these radar
measurements result from the nonlinear behavior of this plasma.
This paper describes a set of high-resolution, 2-D, fully
kinetic simulations of electric field driven turbulence in the
electrojet. These show the saturated amplitude of the waves;
coupling between linearly growing modes and damped modes; the
evolution of the system from dominance by shorter (1 m–5 m) to
longer (10 m–200 m) wavelength modes; and the propagation of the
dominant modes at phase velocities that lie below the linearly
predicted phase velocity and close to but slightly above the
acoustic velocity. These simulations reproduce many of the
observational characteristics of type 1 waves. They provide
information useful in accurately modeling FB turbulence and
demonstrate the significant progress we have made in simulating
the electrojet.
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