Final Report

Theoretical investigation of MHD wave phenomena and oscillations in solar plasmas and interpretation of observations of dynamic and energy release processes in the solar atmosphere formed the primary focus of the project. Special attention was paid to the processes of nonlinear dynamics of MHD waves and the role of the increased amount of the neutral atoms provided by the presence of partially ionized helium and hydrogen in the solar chromospheric and coronal plasmas, which was taken into account in a physically correct self-consistent way. The theoretical part of the project comprised analytic approaches and numerical simulations aimed to quantify the complex dynamical and energy release processes in the solar plasmas. The observational and data analysis activity consisted in application of advanced data analysis techniques to the data from modern space missions and observational programs.

One of the major achievements of the project consists in the development of a generic approach for description of dynamical and wave processes, using the methods of multi-fluid plasma magnetohydrodynamic (MHD). This approach was then applied for the investigation of dispersion properties and propagation features of the fundamental MHD wave-modes important in solar physics. The performed study confirmed the significance of ion-neutral collisions for the energy transport and heating processes in the partially ionized plasmas of the solar photosphere, chromosphere and prominences. It has been shown that also neutral helium may play, along with the neutral hydrogen, an additional important role for energy dissipation in moderately cold (10.000-40.000 K) plasmas of the solar prominences.

Theoretical solar plasma physics studies were combined with the analysis and interpretation of observational data provided by international observer teams cooperating with the project. In particular, the phenomena of transverse oscillations, kink instability, and solitons in magnetic loops of flaring active regions, as well as kink waves in solar spicules were investigated and provided with physical explanations. Besides of that, a new mechanism for interpretation of 5-min oscillations in the solar corona due to the non-linear effects provoked by an initial velocity pulse has been proposed.

In course of the project performance the members of project team initiated several follow-up FWF projects and played leading roles in the research and development consortia of three European projects: SolSpaNet (subdivision leader), Europlanet (subdivision leader), and IMPEx (project coordinator).