Projektbeschreibung
Die Mechanismen geordneter Magnetfelder im Universum verstehen
Weite Teile des Kosmos werden von Magnetfeldern durchdrungen. Eine bemerkenswerte Beobachtung ist, dass kaum eines der Magnetfelder von Himmelskörpern diffus ist, sondern sich fast immer eine geordnete magnetische Struktur zeigt. Dass geordnete Magnetfelder in unserem chaotischen Universum derart vorherrschend sind, hat in der Astronomie zu Irritationen geführt. Nun soll ergründet werden, wo die Felder ihren Ursprung haben und wie sie in diesem Chaos bestehen können. Aktuelle Theorien sind nicht in der Lage ausreichend zu erklären, wie diese Ordnung entsteht, insbesondere bei sonnenartigen Sternen, wie eben unserer Sonne. Die Mitglieder des EU-finanzierten Projekts UniSDyn haben sich vorgenommen, neuartige Werkzeuge für Simulationen und die Datenanalyse zu konzipieren, um die Dynamoprozesse bei Himmelskörpern – die Mechanismen, die die Magnetfelder hervorrufen – genauer beschreiben zu können.
Ziel
Magnetic fields are ubiquitous in the universe. The special property of cosmic magnetism is that, in the majority of objects hosting magnetic fields, those fields are organized, such that some meaningful averaging can reveal global structure and systematic behavior. In the Sun, averaging over longitude reveals the equatorward migration of the emergence region of the sunspots, forming the famous butterfly diagram. Further, vigorous turbulence is present in a wide variety of astrophysical systems, and yet they still exhibit organized magnetic fields. These observations prompt the search for a theory to explain how order can arise and sustain itself in such chaos. We claim that the available theories are incomplete, especially in the case of solar-like stars which becomes apparent if we view the Sun as one star among many. We propose a coherent plan of advancement in which each theory shall be tested by requiring it also to explain the cyclic dynamo action seen in more active rapid rotators.
UNISDYN project attacks these very problems with novel simulations and data analysis tools. Our path to resolve them is to enhance the state-of-the-art stellar dynamo models with the relevant descriptions of the turbulent processes. This goal is reached in three steps. (i) We will produce improved convection dynamo simulations to serve as laboratories from which (ii) the turbulent transport coefficients are directly measured with a novel test methods suite. (iii) Finally, global dynamo models incorporating the turbulent effects in full are constructed based on (i) and (ii) results. These results will allow us to unify stellar dynamo theory for solar-like inactive and rapidly rotating active stars. The developed toolbox has direct applications in other fields of astrophysics, such as accretion and galactic disk dynamos, and industry, such as combustion engines and fusion reactors.
Wissenschaftliches Gebiet
Programm/Programme
Thema/Themen
Finanzierungsplan
ERC-COG - Consolidator GrantGastgebende Einrichtung
02150 Espoo
Finnland