Seminar by Rajab Ismayilli, KU Leuven
Our study investigates the dynamics of unidirectionally propagating surface Alfvén waves, employing magnetohydrodynamic (MHD) numerical simulations and statistical methodologies. Our primary goal is to enhance the understanding of the nonlinear self-cascade of surface Alfvén waves, what we term as uniturbulence, by unraveling the complex relationships between various length scales and their interplay with turbulent energy transfer mechanisms. To achieve this, we extensively analyze uniturbulence using methods such as power spectrum analysis, radially averaged Fourier transform, and kurtosis. We employ these techniques to investigate the spatiotemporal distributions of kinetic and magnetic energy in uniturbulent flows. We also reveal the crucial role of the density contrast's variations and the role of Yaglom's law in characterizing energy transfer mechanisms. Our findings reveal that the inertial range of the perpendicular kinetic energy (KE$_\perp$) and magnetic energy (ME$_\perp$) along the z-axis depict a progressive change in slope values, ultimately approaching the often-observed values of -5/3 and -3/2, respectively. Furthermore, our kurtosis analysis highlights the non-Gaussian behavior of the flow field at different length scales and over time, offering a perspective on uniturbulence dynamics. The correlations observed among diverse statistical approaches emphasize the complex interplay between different length scales in the context of uniturbulence. Our findings contribute to understanding of this phenomenon, establishing a basis for future investigations to clarify the connections regulating these turbulent dynamics.
Host: Michael Hahn