Special Session SS5  27 June 2017

Energy release and radiation in partially ionized plasma of solar and stellar atmospheres

Aims and scope

Recent studies of the Sun with the spacecrafts and ground-based observations challenge the modern models of a solar flare which assumed primary energy release in the corona. It was found that the photosphere and the chromosphere play a significant role in the flaring processes. In addition, the chromosphere is heated in situ to the coronal temperatures without the precipitated particle fluxes probably due to the Joule dissipation of the electric currents. Helioseismic disturbances also manifest an importance of electric currents in the energy release processes in the chromosphere. It suggests that substantial part of the magnetic energy is released directly in the low atmosphere of the Sun. Hence standard solar flare model is not universal. Among various mechanisms of the heating of stellar coronae the special place takes the heating by MHD waves excited in the stellar photosphere and chromosphere. Recent SDO observations have revealed undamped kink oscillations for many hours. Peculiarities of the generation, propagation and dissipation of various MHD modes in a partial ionized medium, promising to heat the corona, it also seems urgent task. The development of technology at millimeter and sub-millimeter wavelengths opens the new opportunity to study the energy release processes in the lower layers of the solar atmosphere, chromosphere and transition layer. The study of the origin of sub-THz and THz radiation from the Sun is a promising new area in the searching of non-steady-state processes in stellar atmospheres. New telescopes of mm and sub-mm range are created including ALMA, Solar-T, and 30 THz solar telescope. The main problem in an unusually intense radio emission from the brown dwarfs is unknown but extremely effective mechanism of charge particle acceleration in partially ionized atmosphere of ultra-cool stars. Dynamics of prominences and their role in the energy release processes are also interesting subject for the Session. Thus, the solution of the problems of the particle acceleration, plasma heating and the radiation in a partially ionized atmospheres of the Sun and the stars will allow us to move towards a better understanding of the physics of solar and stellar flares.

Programme
New observations with ALMA, Solar-T, and 30 THz solar telescope. -Evidences in situ plasma heating in the stellar chromospheres. -Electric currents and electric fields in stellar atmospheres. -Particle acceleration in the in partially ionized atmospheres of the Sun and ultra-cool stars. -Generation and propagation of MHD-waves in photosphere and chromosphere. -Multi-wavelength emission from solar chromosphere. -Dynamics of prominences and their role in the energy release processes. -Magnetic reconnection in partially-ionized plasma.

Invited speakers
- Ch.Helling (School of Physics and Astronomy, University of St Andrews, St Andrews), - H.Hudson (School of Physics and Astronomy, University of Glasgow), - J.-P. Raulin (CRAAM, Universidade Presbiteriana Mackenzie, Sao Paulo),

Scientific organisers
- A.Stepanov (Pulkovo Observatory, St.Petersburg), - P.Kaufmann (Mackenzie Presbyterian University, São Paulo), - E.Kontar (School of Physics and Astronomy, University of Glasgow),

Contact
astep44 @ mail.ru

Updated on Sat Jan 14 07:32:41 CET 2017