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MPS Seminar: Evidence for the two-fluid scenario in solar prominences (E. Wiehr)

  • Date: Aug 23, 2018
  • Time: 13:00 - 14:00
  • Speaker: Eberhard Wiehr
  • Universitätssternwarte Göttingen
  • Location: MPS
  • Room: Auditorium
  • Host: Achim Gandorfer

Doppler shifts of Sr II 4078 in a quiescent prominence give 15% larger velocities than Na D. This is equally found for Fe II 5018 and He I 5015 and suggests a drag effect between ions and neutrals, when moved by the magnetic field. Also the widths of lines from ions systematically exceed those from neutrals, and the non-thermal velocities, responsible for the broadening of lines from massive ions as Sr II and Fe II, are not related to their excess velocities. The emission ratio of Na D and Sr II gives an electron density of 4*10^10 /cm^3. We apply a new wavelength reference from aureola spectra, which is independent of photospheric velocity fields.

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