Seminars at MPS

11240 1507556840

S3 Seminar: The Inner Coma of Comet 67P/Churyumov-Gerasimenko (D. Marshall)

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S3 Seminar: Reconstruction of the Solar Cycle in the Pre-telescope Time (C.-J. Wu)

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12538 1516091869

Planetary Group Seminar: Von Mie bis Multiple Scattering-Methoden zur Simulation der Lichtstreuung von Partikeln (T. Wriedt)

  • Date: Jan 25, 2018
  • Time: 11:00 - 12:00
  • Speaker: Thomas Wriedt
  • University of Bremen (Leibniz-Institut für Werkstofforientierte Technologien, IWT)
  • Location: MPS
  • Room: Auditorium
  • Host: Urs Mall

Zur Simulation der Lichtstreuung oder auch der BRDF von komplexen Strukturen und Partikelschichten muss die Lichtstreuung von Einzelpartikeln simuliert werden. In dem Vortrag wird ein Überblick über die zur Verfügung stehenden Theorien gegeben. [more]

ESPOS

12582 1516369043

ESP Online Seminar: The Magnetic Nature of the Umbra-Penumbra Boundary in Sunspots (J. Jurčák)

Sunspots are the longest known manifestation of solar activity and their magnetic nature has been known for more than a century. Despite this, the boundary between umbrae and penumbrae, the two fundamental sunspot regions, has hitherto been solely defined by an intensity threshold. We now unveil the empirical law of the magnetic nature of the umbra-penumbra boundary in stable sunspots: an invariant vertical component of the magnetic field. We study the magnetic nature of umbra-penumbra boundaries in sunspots of different sizes, morphology, evolutionary stage, and phase of the solar cycle. We use a sample of 88 scans of Hinode/SOT spectropolarimeter to infer the magnetic field properties at the umbral boundaries. We define these boundaries by an intensity threshold and perform a statistically analysis of the magnetic field properties at these boundaries. We statistically prove that the umbra-penumbra boundary in stable sunspots is characterised by an invariant value of the vertical component of the magnetic field: The vertical component of the magnetic field strength does not depend on the umbra size, its morphology, and phase of the solar cycle. With statistical Bayesian inference, we find that the vertical component of the magnetic field strength is, with 99\% likelihood, in the range of 1849-1885 G with the most probable value of 1867 G. In contrast, the magnetic field strength and inclination averaged along individual boundaries are found to be dependent on the umbral size: The larger the umbra, the stronger and more horizontal the magnetic field at its boundary is. [more]

11243 1507557203

S3 Seminar: Global-scale solar equatorial Rossby waves (B. Proxauf)

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