Instabilities in electrically driven rotating MHD layers

Final LIMTECH Colloquium and International Symposium on Liquid Metal Technologies

材料科学;金属学

Mistrangelo, C.^1 ; Bühler, L.^1

Karlsruhe Institute of Technology, P.O.B. 3640, Karlsruhe

76021, Germany^1

关键词: Applied magnetic fields;    Electrically conducting fluids;    Electromagnetic forces;    Intense magnetic fields;    Magnetic field line;    Onset of instabilities;    Supercritical bifurcation;    Uniform magnetic fields;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/228/1/012004/pdf
DOI  :  10.1088/1757-899X/228/1/012004

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Flows of electrically conducting fluids exposed to intense magnetic fields exhibit a common feature i.e. the formation of uniform cores in which electromagnetic forces are dominant. Cores are separated from each other by thin layers that extend along magnetic field lines. Across these parallel layers strong gradients of flow variables are present, which can lead to the onset of instabilities and non-linear flow transitions. In this work we investigate dynamics and stability issues of rotating parallel layers driven by electromagnetic forces caused by the interaction of injected electric currents with an applied magnetic field. The geometry considered consists of two coaxial circular electrodes used for current injection. They are placed in parallel electrically insulating planes perpendicular to a uniform magnetic field. The basic axisymmetric steady state flow, characterized by a rotating velocity jet confined in a parallel layer that connects the rims of the electrodes, is rather well understood. By increasing the driving current above a critical value the basic flow becomes unstable and undergoes a sequence of supercritical bifurcations.