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arXiv 1010.5604astro-ph.SR
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太阳光球中的涡度

Vorticity in the solar photosphere

S. Shelyag, P. Keys, M. Mathioudakis, F. P. Keenan

摘要:

目标。我们使用磁性和非磁性的3D数值模拟的太阳颗粒和G-波段辐射诊断所产生的模型来分析太阳光球中的小尺度涡旋运动的产生。方法.磁对流的辐射MHD模拟用于产生光球模型。我们的出发点是一个非磁性的太阳对流模型,在这里我们引入了一个均匀的磁场,并遵循模拟光球场的演变。我们发现了两种不同类型的光球涡,并提供了一个链接之间的涡的产生和存在的晶间磁场。涡度方程的详细分析,结合G-波段辐射诊断,使我们能够识别模拟光球中光球涡度的来源和观测特征。结果两种不同类型的光球涡,磁性和非磁性,产生的域。非磁涡旋是由光球层中等离子体的斜压运动产生的,而磁涡旋是由颗粒间磁通量浓度中的磁张力产生的。这两种类型的涡具有不同的形状。我们发现,更有效地产生的涡流磁化模型。模拟的G-波段图像显示了磁涡旋和光球亮点旋转运动之间的直接联系,并表明磁亮点旋转和在大气高层观测到的小尺度涡旋运动之间可能存在联系。

英文摘要:

Aims. We use magnetic and non-magnetic 3D numerical simulations of solar granulation and G-band radiative diagnostics from the resulting models to analyse the generation of small-scale vortex motions in the solar photosphere. Methods. Radiative MHD simulations of magnetoconvection are used to produce photospheric models. Our starting point is a non-magnetic model of solar convection, where we introduce a uniform magnetic field and follow the evolution of the field in the simulated photosphere. We find two different types of photospheric vortices, and provide a link between the vorticity generation and the presence of the intergranular magnetic field. A detailed analysis of the vorticity equation, combined with the G-band radiative diagnostics, allows us to identify the sources and observational signatures of photospheric vorticity in the simulated photosphere. Results. Two different types of photospheric vorticity, magnetic and non-magnetic, are generated in the domain. Nonmagnetic vortices are generated by the baroclinic motions of the plasma in the photosphere, while magnetic vortices are produced by the magnetic tension in the intergranular magnetic flux concentrations. The two types of vortices have different shapes. We find that the vorticity is generated more efficiently in the magnetised model. Simulated G-band images show a direct connection between magnetic vortices and rotary motions of photospheric bright points, and suggest that there may be a connection between the magnetic bright point rotation and small-scale swirl motions observed higher in the atmosphere.

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