Spectral diagnostics of active prominences

Labrosse, N., Gouttebroze, P. and Vial, J.-C. (2007) Spectral diagnostics of active prominences. In: Heinzel, P., Dorotovic, I. and Rutten, R.J. (eds.) The Physics of Chromospheric Plasmas: Proceedings of the Coimbra Solar Physics Meeting Held at the University of Coimbra, Coimbra, Portugal, 9-13 October, 2006. Series: Astronomical Society of the Pacific conference series (368). Astronomical Society of the Pacific: San Francisco, USA, pp. 337-343. ISBN 9781583812365

Abstract

Active prominences exhibit plasma motions, resulting in difficulties with the interpretation of spectroscopic observations. These solar features being strongly influenced by the radiation coming from the solar disk, Doppler dimming or brightening effects may arise, depending on which lines are observed and on the velocity of the plasma. Interlocking between the different atomic energy levels and non local thermodynamic equilibrium lead to non-trivial spectral line profiles, and this calls for complex numerical modelling of the radiative transfer in order to understand the observations. We present such a tool, which solves the radiative transfer and statistical equilibrium for H, He I, He II, and Ca II, in moving prominences where radial plasma motions are taking place. It is found that for isothermal, isobaric prominence models, the He II resonance lines are very sensitive to the Doppler effect and show a strong Doppler dimming. The Ca II lines are not very sensitive to the Doppler effect for the prominence models considered here. We illustrate how the code makes it possible to retrieve the plasma thermodynamic parameters by comparing computed and observed line profiles of hydrogen and helium resonance lines in a quiescent prominence.

• Item Type: Book Sections
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Labrosse, Dr Nicolas
• Authors: Labrosse, N., Gouttebroze, P., and Vial, J.-C.
• Subjects: Q Science > QB Astronomy; Q Science > QC Physics
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Publisher: Astronomical Society of the Pacific
• ISBN: 9781583812365