Die Erzeugung und Dissipation von solaren Magnetfeldern

宇宙磁场的产生、演化和耗散是天体物理学的基本问题之一。太阳作为离我们最近的恒星，提供了一个独特的机会来了解磁场是如何与动态等离子体相互作用的：它是移动的电离气体的作用，对产生磁场至关重要。太阳光球表现出电离等离子体对流区的上界，从那里产生磁场，逃逸到行星际空间。在光球层中，磁场存在于很大的空间尺度上：从大小为几百公里或更小的磁元素到典型直径为3万公里的太阳黑子。该项目将利用独特的数据来源来提高我们对太阳磁场的理解：(1)我们将分析2009年6月在平流层气球上飞行的1米SUNRISE太阳望远镜的数据。这次任务获得了安静太阳的最好的光谱偏振数据。这些数据可以用来分析磁场是如何产生、演变和最终消散的。(2) 2009年7月，在德国真空塔望远镜上，我们在极好的观测条件下见证了太阳黑子的形成。我们用两个光谱偏振仪和成像装置观察了形成过程。这组数据的质量和完整性将有助于解决长期存在的问题，即磁场是如何形成太阳黑子的。

The generation, evolution, and dissipation of cosmic magnetic fields is one of the fundamental problems in astrophysics. The Sun as the closest star offers the unique opportunity to gain understanding of how magnetic fields interact with dynamic plasma: it is the action of moving ionized gas that is crucial for generating magnetic field. The solar photosphere manifests the upper boundary of a convection zone of ionized plasma, from which magnetic fields emerge, escaping into interplanetary space. In the photosphere the magnetic fields exist on a large range of spatial scales: from magnetic elements with sizes of a few hundred km or less to sunspots which a typical diameter of 30 000 km.This project will take advantage of unique sources of data that allow to improve our understanding of solar magnetic fields: (1) We will analyze data from the 1m SUNRISE Solar telescope that flew on a stratospheric balloon in June 2009. This mission has acquired the best-ever spectropolarimetric data of the quiet Sun. These data will allow to analyze how magnetic field emerges, evolves and eventually dissipates. (2) At the German Vacuum Tower Telescope, in July 2009, we have witnessed the formation of a sunspot under excellent seeing conditions. We have observed the formation process with two spectro-polarimeters and imaging devices. This data set of extraordinary quality and completeness will allow to address the long standing problem of how magnetic field emerges to form sunspots.