Scaling properties of turbulent convection in two-dimensional periodic systems

The statistical properties of turbulent convection are studied numerically in a 2D periodic system relevant for a strongly magnetized plasma. Both cases of unstable and stable stratification are considered. In spite of the anisotropic driving, the spectra are almost perfectly isotropic. In the unstable case the density fluctuation spectrum is E-k(N) similar to k(-1.2), flatter than the Bolgiano spectrum similar to k(-1.4), and the structure functions exhibit strong intermittency, the relative scaling exponents being similar to those of a passive scalar. In the stable case the spectrum is closer to the Bolgiano spectrum and intermittency is much weaker.