Freiburg 2008 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 8: The Sun and Heliosphere II

EP 8.4: Vortrag

Dienstag, 4. März 2008, 17:30–17:45, KGI-Aula

Quasi-oscillations between two turbulent regimes in 2D magnetoconvection — •Dan Škandera and Wolf-Christian Müller — Max-Planck-Institute for Plasma Physics, 85748 Garching, Germany

Spectral and statistical properties of two-dimensional turbulent magnetoconvection are studied by means of direct numerical simulations in the frame of Boussinesq magnetohydrodynamic (MHD) approximation. Turbulent fluctuations are driven by a mean horizontal temperature gradient. The spectra of kinetic and total energy indicate that during its time evolution the investigated system performs quasi-oscillations with time periods of turbulence dominated by nonlinear MHD interactions and turbulence dominated by buoyancy. It is shown that the presence of a particular turbulent regime depends on the mutual alignment between velocity and magnetic field. In addition, a simple phenomenological model that explains the observed quasi-oscillations is presented.