Journal Article

Nonequilibrium Processes in the Solar Corona, Transition Region, Flares, and Solar Wind (Invited Review)

Del Zanna, Giulio, Vocks, Christian, Krucker, Säm, Sylwester, Barbara, Meyer-Vernet, Nicole, Williams, David R., Mackovjak, Šimon, Giunta, Alessandra, Sylwester, Janusz, Mason, Helen E., Dzifčáková, Elena, Dudík, Jaroslav, Matteini, Lorenzo, Young, Peter R., Oka, Mitsuo

2017

Overview

We review the presence and signatures of the non-equilibrium processes, both non-Maxwellian distributions and non-equilibrium ionization, in the solar transition region, corona, solar wind, and flares. Basic properties of the non-Maxwellian distributions are described together with their influence on the heat flux as well as on the rates of individual collisional processes and the resulting optically thin synthetic spectra. Constraints on the presence of high-energy electrons from observations are reviewed, including positive detection of non-Maxwellian distributions in the solar corona, transition region, flares, and wind. Occurrence of non-equilibrium ionization is reviewed as well, especially in connection to hydrodynamic and generalized collisional-radiative modeling. Predicted spectroscopic signatures of non-equilibrium ionization depending on the assumed plasma conditions are summarized. Finally, we discuss the future remote-sensing instrumentation that can be used for the detection of these non-equilibrium phenomena in various spectral ranges.

• Publisher: Springer Netherlands,Springer Nature B.V,Springer Verlag
• Subject: Astrophysics / Astrophysics and Astroparticles / Atmospheric Sciences / Corona / Equilibrium / Heat flux / Instrumentation / Invited Review / Ionization / Nonequilibrium ionization / Physics / Physics and Astronomy / Remote sensing / Signatures / Solar corona / Solar flares / Solar physics / Solar transition region / Solar wind / Space Exploration and Astronautics / Space Sciences (including Extraterrestrial Physics