Seminars at MPS

Interested visitors are very welcome to join in all seminars held and talks given at the MPS. The presentations are mainly given in English. More detailed information can be found at the seminars' pages.

Invited guest scientists of other institutes report on the successes and results of their research in institute seminars and colloquia.

PhD students of the International Max Planck Research School (IMPRS) present their work in S3 seminars.

In the Seminars about Planets and Comets, as well as in the Seminars about the Sun and sunlike Stars, the scientists of the respective departments report on the latest results and progress made in their projects and introduce new missions. All seminars are concluded with a short discussion or a questions-and-answers sessions.

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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. [more]
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Immense volcanism and extraterrestrial impact are the two main suspects in driving the Cretaceous-Palaeogene (K-Pg) mass extinction, but incontrovertible empirical evidence for how either caused ecological collapse has up to now been scant. In my talk I will present new boron isotope data revealing rapid fluctuations in ocean pH and atmospheric pCO2 at the K-Pg, indicating ocean acidification caused by impact, not volcanism, prompted marine mass extinction. Furthermore, by coupling with earth system models, our pH estimates allow us to solve a longstanding geological puzzle: what was the cause of the post-extinction collapse in surface-deep carbon isotope gradients in the ocean, and what does it convey about the Earth’s ecological recovery after the mass extinction event? [more]
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S3 Seminar: Properties of Sunspot Penumbrae (Kamal Sant)

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Öffentlicher Vortrag [more]
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