Differential rotation of the Sun and magnetic diffusivity after the Maunder minimum as well as numerical models of the solar dynamo

太阳的微分旋转和蒙德极小期后的磁扩散率以及太阳发电机的数值模型

• 批准号: 149259345
• 负责人: Dr. Rainer Arlt
• 金额: --
• 依托单位: Leibniz-Institut für Astrophysik Potsdam (AIP)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/149259345?language=en
• 关键词: Differential; rotation; Sun; magnetic; diffusivity

Sunspots are the key indicator for solar activity, since we have information about them for about 400 years. The positions of sunspots have been utilized only since 1874. During the Maunder minimum period in the 17th century, very few spots were observed, in order to fill the gap between the measurements starting in 1874 and the scattered observations known from the Maunder minimum, we plan the precise analysis of about 1000 observations made by in 1749-1796. The differential rotation of the Sun in the 18th century as well as the magnetic diffusivity at that time will be determined, and a search for active longitudes will be performed. North-south asymmetries and the coherence of the cycle in the northern and southern hemispheres will be studied. The solar images will be made accessible to the Virtual Solar Observatory.The work will include theoretical modelling of dynamo processes that can lead to the observed behaviour, based on the measured differential rotation and diffusivity shortly after the Maunder minimum. We are particularly addressing the issues of helicity fluxes necessary to allow for dynamos growing fast enough and to high enough saturation amplitudes. While most of these studies were performed in Cartesian boxes, we plan to run simulations in spherical shells, based on both driven helical turbulence and more realistic convection.

太阳黑子是太阳活动的关键指标，因为我们有大约400年的信息。太阳黑子的位置自1874年以来才被利用。在17世纪的蒙德极小期，观测到的黑子非常少，为了填补1874年开始的测量和蒙德极小期已知的零散观测之间的差距，我们计划对1749-1796年的大约1000个观测进行精确分析。将确定太阳在18世纪的差异旋转以及当时的磁扩散率，并将进行活动星系的搜索。将研究南北不对称性以及北方和南方半球周期的连贯性。太阳图像将提供给虚拟太阳观测台，这项工作将包括根据蒙德极小期后不久测得的差速旋转和扩散率，对可能导致观测到的行为的发电机过程进行理论建模。我们特别要解决螺旋度通量的问题，这是使发电机增长足够快和足够高的饱和振幅所必需的。虽然大多数这些研究都是在笛卡尔盒子中进行的，但我们计划在球壳中进行模拟，基于驱动螺旋湍流和更现实的对流。