Freiburg 2008 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 7: The Sun and Heliosphere I

EP 7.2: Hauptvortrag

Dienstag, 4. März 2008, 14:30–15:00, KGI-Aula

The magnetic field of the quiet Sun — •Oskar Steiner — Kiepenheuer-Institut für Sonnenphysik, Freiburg

In the past year the Sun’s surface appeared often featureless and smooth since we are now in a minimum phase of the solar cycle. Over periods of months, no sign of magnetic activity was visible. And yet, even the most quiescent surface area harbors ample amounts of magnetic field as is now clearly revealed by long exposure magnetognetograms with the new Japanese space observatory Hinode. What is the physical nature of this magnetic field and where does it stem from? This presentation highlights some aspects of the quiet Sun magnetic field. It is shown how three-dimensional magnetohydrodynamic simulations can help us in answering these questions, but not without validation by close comparison with observations. In order not to go astray with too abstract model concepts, we must take care keeping the simulations realistic enough for enabling the computation of synthetic spectro-polarimetric quantities that can be directly compared with true observations. It is demonstrated how this interaction between simulation, the production of synthetic observation, and subsequent comparison with true observations works, and how it can help us in understanding the Sun’s magnetic character.