Berlin 2024 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 32: Poster: Active Matter, Soft Matter, Fluids

DY 32.25: Poster

Wednesday, March 20, 2024, 15:00–18:00, Poster C

Spatio-temporal correlation in MHD turbulence — •Raquel Mäusle and Wolf-Christian Müller — Technische Universität Berlin, Berlin, Germany

Turbulent flows are ubiquitous on Earth and throughout the universe. They can be understood as the superposition of turbulent fluctuations on various spatial and temporal scales. Energy is transferred between these scales through non-linear interactions, a process known in 3D as the direct energy cascade. We study this energy transfer process by computing the spatio-temporal correlation between fluctuations in magnetohydrodynamic turbulence. To this end, we employ direct numerical simulations, in which the fluctuations are measured in a quasi-Lagrangian manner to avoid the sweeping effect. This framework was used in previous studies of Navier-Stokes turbulence [Physics of Fluids 23.8 (2011):085107], which we extended to account for the anisotropy introduced by the presence of the magnetic field. We present the resulting correlation time scale, strength and direction of the cross-scale energy transfer in the directions parallel and perpendicular to the local magnetic field and relate them to phenomenological models of MHD turbulence. Furthermore, the limitations of the quasi-Lagrangian framework are discussed.

Keywords: Turbulence; Magnetohydrodynamics; Correlation