Subgrid modeling of convective turbulence in weakly ionized collisional plasma by renormalization group analysis
- Univ. of Western Ontario, London (Canada)
- Cornell Univ., Ithaca, NY (United States)
The equations governing the nonlinear evolution of density fluctuations in a low-pressure weakly ionized plasma driven unstable by the ExB or gradient-drift instability were derived by Sudan and Keskinen for addressing the electrostatic turbulence in the E and F regions of the Earth`s ionosphere. The authors have developed a subgrid model suitable for the numerical simulation of these equations which is closely related to renormalized diffusion caused by small-scale fluctuation spectrum. {open_quotes}Dynamical Renormalization Group{close_quotes} (RNG) methods are employed to obtain the renormalized diffusion. This procedure computes the long-wavelength, long-time behavior of density correlations generated by the evolution equation for the plasma stirred by a Gaussian random force characterized by a correlation function {proportional_to} k{sup m} where k is the wavenumber of the forcing function. The effect of small scales on the large-scale dynamics in the limit k{yields}0 and infinite Reynolds number can be expressed in the form of renormalized coefficients; in this case, renormalized diffusion. If one assumes the power spectra to be given by the Kolmogorov argument of cascading of energy through k space then one can derive a subgrid model based on the results of RNG. 27 refs.
- OSTI ID:
- 207166
- Journal Information:
- Journal of Geophysical Research, Vol. 100, Issue A3; Other Information: PBD: 1 Mar 1995
- Country of Publication:
- United States
- Language:
- English
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