Flows and magnetic fields of sunspots at high spatial resolution

点击翻译按钮获取中文摘要

Sunspots, detected in Europe in the early 17th century, have remained fascinating research objects on the Sun. Their magnetic fields, interacting with the ionized gas, give rise to high structuring and constitute a paradigm for the dynamic processes in astrophysical plasmas. Sunspots with their dark umbrae, with their filamentary penumbrae, and with their nearby magnetic activity, are still enigmatic. Our knowledge is limited mainly due to insufficient spatial resolution of the observations. Yet since few years, solar telescopes were equipped with Adaptive Optics (AO), and post-facto image restoration has become in regular use. New findings by our group, achieved with image reconstruction but without AO, gave hints on how to reconcile earlier, contradictory descriptions of the intensity, magnetic field, and velocity fluctuations in sunspots. Substantially improved observations of sunspots have been obtained in 2005 with the new two-dimensional ¿Göttingen¿ Fabry-Pérot spectrometer at the German solar telescope on Tenerife. The observations were supported by AO supplied by the Kiepenheuer-Institut/Freiburg. Refinements of data analysis and interpretation will lead to measurements of flow velocities and magnetic fields with the required high spatial resolution. We will thus contribute to the understanding of the mechanisms causing the dynamic behavior of sunspots.