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Conference Serie
6th international workshop on solar and stellar magnetic fields Free Conference is closed
Conference is closed
BK2016
Affiliation University of Graz, IGAM
Bairisch-Kölldorf, Austria
24.04.2016 - 27.04.2016

Organizing institutions
University of Graz, Institute of Physics, IGAM
Main category Natural Sciences (Physics)
Conference/Workshop objectives

The workshop is dedicated to the solar Photosphere and Chromosphere from the perspective of high resolution solar observations and simulations. The goal of the meeting is to strengthen the understanding of the coupling among different layers - the convection zone and the lower solar atmosphere - by comparing observations with results from simulations.

Local organizing committee
Arnold Hanslmeier; Lemmerer Birgit; Isabell Piantschitsch; Teimuraz Zaqarashvili
Scientific organizing committee (SOC) Arnold Hanslmeier; Lemmerer Birgit; Isabell Piantschitsch; Teimuraz Zaqarashvili
Sessions
  • Solar and stellar activity, convection zone and photosphere
  • Solar Photosphere
  • Solar Chromosphere
  • Waves and Instabilites
  • Solar Corona and Prominences
  • CMEs and heliosphere
Programme
Invited speakers
Important dates
Registration and payment information
Conference venue Bairisch-Kölldorf, Austria
Hotel information
Travel information
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Michal Sobotka

Session: Solar Chromosphere

1135 views
Date of upload:
07.06.2016
Co-author:
P. Heinzel, M. Švanda, J. Jurčák, D. del Moro, F. Berrilli
Caption:
Time series of Ca II line-center images (69 minutes, 80 frames) and the region of interest.
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Michal Sobotka

Session: Solar Chromosphere

797 views
Date of upload:
07.06.2016
Co-author:
P. Heinzel, M. Švanda, J. Jurčák, D. del Moro, and F. Berrilli
Abstract:
Several mechanisms may heat the solar chromosphere: acoustic waves, magnetoacoustic waves (slow, fast, and Alfven waves), and small-scale magnetic reconnections. Based on observations in the Ca II 854.2 nm line, the contribution of acoustic waves to the heating of quiet and plage regions in the chromosphere is discussed. The point is to compare the energy released by radiative losses with the energy deposited by acoustic waves. Radiative losses are computed using a grid of semi-empirical chromospheric models. The deposited acoustic flux is calculated using power spectra of Doppler oscillations measured in the Ca II line core. The comparison shows that the spatial correlation of maps of radiative losses and acoustic flux is 72 %. The deposited acoustic flux covers only 15 % of radiative losses in quiet chromosphere but 23 % in network and 54 % in plage areas. This estimate is a lower limit of the real acoustic energy flux.
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Martin Leitzinger

Session: Solar Corona and Prominences

860 views
Date of upload:
09.06.2016
Co-author:
P. Odert, T. Zaqarashvili, R. Greimel, A. Hanslmeier, H. Lammer
Abstract:
Prominences are manifestations of solar/stellar coronal magnetic fields. Coronal magnetic field supports cool dense prominence plasma against gravity, which may be kept for several rotations (quiescent prominences) or may be ejected because of disturbances in the stellar plasma causing the plasma to accelerate very fast (eruptive prominences). On the Sun, prominences are known to exhibit oscillations, so-called small- and/or large-amplitude oscillations, which show amplitudes of a few km/s for small amplitude oscillations and >20 km/s for large amplitude oscillations. The periods of large amplitude oscillations are in the range of 6-150~min. So far no prominence oscillations have been detected on stars. With existing observatories the stellar analogue of large-amplitude oscillations can be searched on stars which are known to host prominences. Furthermore, stars hosting prominences are good targets for searching for stellar mass ejections, because erupting filaments and mass ejections (CMEs) are closely correlated on the Sun, moreover the CME core often represents the filament itself. We present the analysis of six nights of optical spectroscopic monitoring of the young and fast rotating stars HK Aqr and PZ Tel, which are known to host prominences. We detect on both stars prominences. In two prominences on HK Aqr we detect indications of prominence oscillations reminiscent to solar large amplitude oscillations, at least with period. We detect no oscillations in the prominences of PZ Tel. Furthermore we find no eruptive prominences on both stars. We explain the non-existence of eruptive prominences using geometrical considerations.
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