Solar prominences are usually presented as relatively quiet structures where the plasma and the magnetic field do not exhibit significant large-scale changes, unless an eruption takes place. The most recent observations of the Sun’s atmosphere however reveal a paradox: the vivid and sometimes chaotic movements seen in both cool and hot plasma in and around some prominences are in contrast with the apparently stable and long-lived magnetic field topology measured with state-of-the-art techniques in that very same plasma. The goal of this International Team is to test new ideas and develop new models to explain 1) how the motions observed in prominences (above the solar limb) and filaments (on the solar disk) fit with our current understanding of the magnetic field structure, and 2) how these motions are related to the photospheric dynamics. We will focus on structures revealing complex plasma motions which are difficult to interpret without an in-depth understanding of the underlying magnetic structure. These structures often coincide with prominence feet, where the general magnetic topology is perturbed by photospheric parasitic magnetic polarities. The proposed International Team will include 12 experts of all the aspects involved in tackling these challenging questions: observations across the EM spectrum (from EUV to mm wavelengths) including spectroscopy, radiative transfer, photospheric dynamics, magnetic field models, and polarimetry. Over two meetings, this International Team will analyse data obtained during previous campaigns (e.g. with THEMIS, the Dutch Open Telescope, Meudon and Ondrejov spectrographs, the Solar Dynamics Observatory, Hinode and IRIS), and during future campaigns including new observations with ALMA (planned as part of a proposal for Cycle 4 observations). Combined with an exploration of recent and new prominence models, we will aim to build the most consistent picture to date of these dynamical prominences.

Core team members and expertise

  • Lucie Green (MSSL, UK): evolution of the Sun’s magnetic field; onset and magnetic configuration of eruptive events.
  • Stanislav Gunár (Astronomical Institute of the Czech Academy of Sciences, Ondřejov, CZ): prominence fine structure modelling; multi-dimensional radiative transfer modelling.
  • Petr Heinzel (Astronomical Institute of the Czech Academy of Sciences, Ondřejov, CZ): theory of radiative transfer; optical, UV and EUV spectroscopy; radiation hydrodynamics.
  • Terry Kucera (NASA/GSFC, USA): EUV observations and data analysis of prominences (spectroscopy, images).
  • Nicolas Labrosse (Univ. of Glasgow, UK – Leader): 1D and 2D radiative transfer modelling; UV and EUV spectroscopic diagnostics; synthetic spectra.
  • Arturo López Ariste (IRAP, FR): spectropolarimetry; inversion techniques; magnetic field measurements.
  • Manuel Luna (IAC, SP): prominence wave and oscillations modeling and observations; prominence formation.
  • Duncan Mackay (Univ. of St Andrews, UK): MHD simulations of prominence formation and evolution; direct assimilation of observational data into theoretical models.
  • Olga Panasenco (Advanced Heliophysics, USA): formation and magnetic topology, stability and eruption of solar filaments; space- and ground-based observations and data analysis.
  • Thierry Roudier (IRAP, FR): feature tracking (e.g. LCT and CST).
  • Brigitte Schmieder (LESIA, Paris Observatory, FR): spectroscopic diagnostics of the solar atmosphere; ground- and space-based joint observations and data analysis.
  • Sven Wedemeyer (ITA, Univ. of Oslo, NO): ALMA observations; structure, dynamics, and energy balance of the solar atmosphere.

Additional participants

  • Jack Jenkins (MSSL): Young Scientist
  • Tom Rees-Crockford (Northumbria): Young Scientist
  • Andrew Rodger (Glasgow): Young Scientist
  • Peter Levens (Glasgow): Young Scientist
  • Sonja Jejčič (Ljubljana / Ondřejov)
  • Maciej Zapior (Ondrejov)

The team held its first meeting at ISSI during 6-10 February 2017 in Bern.

The second and final meeting took place 20-23 March 2018 in Bern.

The team at its February 2017 meeting. From let to right at the back: Manuel Luna, Andrew Rodger, Arturo López Ariste, Maciej Zapior, Brigitte Schmieder, Stanislav Gunár, Duncan Mackay, Lucie Green, and Peter Levens. From left to right at the front: Terry Kucera, Nicolas Labrosse, Petr Heinzel.