Regensburg 2025 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 27: Poster: Nonlinear Dynamics, Pattern Formation, Granular Matter

DY 27.14: Poster

Wednesday, March 19, 2025, 15:00–18:00, P4

Self-assembly of Eiffel Towers out of a ferrogranular gas — •Matthias Biersack, Ali Lakkis, and Reinhard Richter — University of Bayreuth, Experimental Physics 5, Universitätsstr. 30, 97440 Bayreuth, Germany

We are exploring in experiments a shaken granular mixture of glass and magnetized steel beads, filled in a horizontal vessel [1]. For strong shaking amplitude (Γ> 3 g) we observe a ferrogranular gas. By means of a Helmholtz-pair of coils we apply a homogeneous magnetic field oriented normal to the vessel. Then we observe the self-assembly of ferrogranular crests resembling miniatur Eiffel Towers. Our findings are compared with the normal field instability emerging in a ferrofluid [2].
[1] M. Biersack, A. Lakkis, R. Richter, O. Bilous, P. A. Sánchez, S. S. Kantorovich Phys. Rev. E, 108 (2023) 054905.
[2] M. Cowley, R. E. Rosensweig J. Fluid Mech. 30 (1967) 671.

Keywords: magnetized granulate; susceptible dipolar hard spheres; pattern formation; growth dynamics; phase separation