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Eye catcher

The Tayler Instability

Whenever an electric current flows through a liquid conductor, the Tayler instability may appear. If the electric current exceeds a value in the order of kiloampère (depending on the material), it will drive a fluid flow. The Tayler instability was observed experimentally for the first time at HZDR (Seilmayer et al., Phys. Rev. Lett. 108 (2012), 244501). A current of up to 8 kA was applied to a column filled with the liquid metal GaInSn (fig. 1). For currents larger than 2.5 kA a flow as illustrated in fig. 2 can be observed.

   Experiment Tayler instability     Fluid flow of the Tayler instability in the experiment        Flow Tayler instability
Fig. 1: Experimental setup of the Tayler instability.

Fig. 2: Simulated flow field of the Tayler instability in the experiment.

The Tayler instability is known to limit the scalability of liquid metal batteries. It will appear first in the upper metal layer; if the flow becomes too strong, it may wipe away the thin electrolyte layer, and short-circuit the cell (fig. 3). At HZDR we are developing different countermeasures for avoiding the Tayler instability and the short-circuit (fig. 4). In order to perform these studies, we developed a fully three-dimensional numerical code using an integro-differential equation approach, and implemented it into the open source CFD software OpenFOAM.

Tayler instability short circuit

Fig. 3: The Tayler instability may short-circuit a liquid metal battery, if the cell current is very large.

Stabilisation Tayler instability

Fig. 4: The Tayler instability in liquid metal batteries can be avoided by many different means.

Besides of liquid metal batteries, the TI is heavily discussed in astrophysics, e.g. for the chemical mixing in stars, the appearance of helical structures in cosmic jets or in context with the Tayler-Spruit dynamo. Recently observed helicity oscillations and their possible synchronisation with planetary forces may potentially help to explain the 11-year sunspot cycle.



Dr. Frank Stefani
Phone: +49 351 260 3069