Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf
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Towards new cutting edge MRI experiments
We present recent progress on the development of standard MRI and its variants -- helical and azimuthal MRI -- in a liquid sodium cylindrical Taylor-Couette (TC) flow in connection with a new large-scale experimental campaign planned at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), which is devoted to the detection of this instability in the lab. Currently, a new TC experimental device is under construction and will be put in operation in 2022. In preparation for these experiments, we performed targeted linear and nonlinear study of MRI for those values of key parameters (Lundquist, Reynolds, magnetic Prandtl numbers, etc) relevant for the upcoming experiments and show its feasibility under new experimental conditions. After that we will present the current status and preparatory work for these experiments at HZDR. Due to very small magnetic Prandtl numbers of liquid metals used, the Reynolds numbers needed to excite MRI in experiments are extremely high, of the order of million. For this reason the instability has always remained evasive in the previous TC experiments. The large size of the experimental device and a wide range of rotation rates are among the main advantages of our new TC device, which offer a unique possibility to reach such high Reynolds numbers and hence to capture MRI in the lab. However, a careful further analysis is required in this case to correctly disentangle MRI modes from other possible instabilities at high Reynolds numbers arising in a finite-length TC flow under the effect of the top and bottom endcaps.
Keywords: Taylor-Couette flow; Magnetohydrodynamics; Magnetorotational instability
Invited lecture (Conferences)
Spinning Fluids 2021: Laboratory Fluid Dynamics for Disks and Planets, 05.-10.09.2021, Ringberg Castle, Kreuth, Bavaria, Germany