Seminare am MPS

 

Zu allen Seminaren und Vorträgen am MPS sind interessierte Besucher herzlich willkommen. Die Präsentationen werden hauptsächlich in englischer Sprache gehalten, genauere Informationen zu Themen, Rednern und Terminen sind auf den einzelnen Seminar-Seiten zu finden.

Bei Institutsseminaren und Kolloquien präsentieren geladene Gastwissenschaftler anderer Institute Erfolge und Resultate ihrer Forschung.

In den S3 Seminaren erklären Doktoranden der Internationalen Max Planck Research School (IMPRS) ihre Arbeit.

In den Seminaren über Planeten und Kometen (PGS) sowie den Seminaren über die Sonne und sonnenähnlicher Sterne (SSGS), berichten die Wissenschaftler aus den jeweiligen Abteilungen über neueste Ergebnisse und Fortschritte in ihren Projekten und stellen neue Missionen vor. Bei allen Seminaren findet im Anschluss an den Vortrag eine kurze Diskussions- bzw. Fragerunde zum Thema statt.

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The magnetic Rayleigh–Taylor instability is a fundamental MHD instability and recent observations show that this instability develops in the solar prominences. We analyze the observations from Solar Dynamic Observatory/Atmospheric Imaging Assembly of a MRT unstable loop-like prominence. Initially, some small-scale perturbations are developed horizontally and vertically at the prominence-cavity interface. These perturbations are associated with the hot and low dense coronal plasma as compared to the surrounding prominence. The interface supports magneto-thermal convection process, which acts as a buoyancy to launch the hot and low denser plumes (P1 and P2) propagating with the speed of 35–46 km s-1 in the overlying prominence. The self-similar plume formation initially shows the growth of a linear MRT-unstable plume (P1), and thereafter the evolution of a nonlinear single-mode MRT-unstable second plume (P2). A differential emission measure analysis shows that plumes are less denser and hotter than the prominence. We have estimated the observational growth rate for both the plumes as 1.32±0.29×10−3 s−1 and 1.48±0.29×10^−3 s^−1, respectively, which are comparable to the estimated theoretical growth rate (1.95×10^−3 s^−1). Later, these MRT unstable plumes get stabilize via formation of rolled (vortex-like) plasma structures at the prominence-cavity interface in the downfalling plasma. These rolled-plasma structures depict Kelvin-Helmholtz instability, which corresponds to the nonlinear phase of MRT instability. However, even after the full development of MRT instability, the overlying prominence is not erupted. Later, a Rayleigh-Taylor unstable tangled plasma thread is evident in the rising segment of this prominence. This tangled thread is subjected to the compression between eruption site and overlying dense prominence at the interface. This compression initiates strong shear at the prominence-cavity interface and causes Kelvin-Helmholtz vortex-like structures. Due to this shear motion, the plasma downfall is occurred at the right part of the prominence–cavity boundary. It triggers the characteristic KH unstable vortices and MRT-unstable plasma bubbles propagating at different speeds and merging with each other. The shear motion and lateral plasma downfall may initiate hybrid KH-RT instability there. [mehr]
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S3 Seminar: Properties of Sunspot Penumbrae (Kamal Sant)

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Der Sonne so nah: Solar Orbiter: Startschuss für eine Sonnenmission der Extreme (Joachim Woch)

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