Laboratory experiments and numerical simulations on magnetic instabilities

随着在里加、卡尔斯鲁厄和卡达拉切进行的发电机实验的成功，建立了一个致力于研究发电机在液态金属流动中的作用的国际社区。目前，液态金属实验的重点正在转向更好地理解磁不稳定性和旋转流动中的波动现象。其中最突出的是磁旋转不稳定性（MRI），它不仅对黑洞和原恒星周围吸积盘的不稳定至关重要，而且可能在行星发电机的角动量输运中起重要作用。磁共振成像出现的证据是最近在螺旋磁场影响下的圆柱形Taylor-Couette实验PROMISE（波茨坦-罗森多夫磁不稳定性实验）中获得的。该项目旨在开发和加强现有的实验基础，以进一步研究相关但非轴对称的磁不稳定性：方位MRI，磁化球形Couette流中的第一不稳定性和泰勒不稳定性。实验将辅以数值工作，特别侧重于小磁普朗特数流的模拟。

With the successful dynamo experiments in Riga, Karlsruhe and Cadarache a worldwide community has been established whose activities are devoted to the investigation of dynamo action in liquid metal flows. Presently, the focus of liquid metal experiments is shifting towards a better understanding of magnetic instabilities and wave phenomena in rotating flows. Most prominent among them is the magnetorotational instability (MRI) which is not only essential in destabilizing accretion disk around black holes and protostars, but which might also play an important role in the angular momentum transport in planetary dynamos. Evidence for the appearance of MRI was obtained recently with the cylindrical Taylor-Couette experiment PROMISE (Potsdam ROssendorf Magnetic InStability Experiment) under the influence of a helical magnetic field. The project is intended to exploit and strengthen the existing experimental basis for further investigations of related but nonaxisymmetric magnetic instabilities: the azimuthal MRI, the first instabilities in a magnetized spherical Couette flow, and the Tayler instability. The experiments will be supported by accompanying numerical work, with particular focus on simulations of small magnetic Prandtl number flows.