MPS Seminar: Evidence for the two-fluid scenario in solar prominences (E. Wiehr)
- Datum: 23.08.2018
- Uhrzeit: 13:00 - 14:00
- Vortragende(r): Eberhard Wiehr
- Universitätssternwarte Göttingen
- Ort: MPS
- Raum: Auditorium
- Gastgeber: 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.