Investigation of exoplanetary magnetic fields and their role in evolution of planetary systems is closely connected with study of the whole complex of stellar-planetary interactions, including the stellar radiation and plasma flow impacts, as well as gravitational interaction effects. Magnetic fields, those connected with the planetary intrinsic magnetism, and fields associated with the electric current systems induced in the surrounding plasma, form the planetary magnetosphere. Magnetosphere acts as an obstacle, which interacts with the stellar wind and protects the planetary ionosphere and atmosphere against the direct impact of the stellar plasmas and energetic particles. The closer the planet is to the star, the stronger are these impacts, and therefore, the more important becomes magnetospheric protection of a planet. The subject of SP6 sub-project of the National Key Program “Pathways to habitability” (NFN S116) over the whole duration of the program consists in investigation of physical mechanisms which determine the structure, topology and dynamics of an exoplanetary magnetosphere with the purpose to understand its nature of and role in planetary evolution.
In the next period, SP6 will continue investigation and modelling of formation and scaling of exoplanetary magnetospheres, taking into account the processes associated with the stellar radiative energy input, as well as the stellar-planetary system features, e.g., type of planet and host star, orbital location, internal and external magnetic field. This study is based on the developed during the first period of the project advanced hydrodynamic and magnetohydrodynamic models of the expanding planetary plasma wind as well as the generalized paraboloid magnetosphere model of exoplanet. Primary attention will be paid to self-consistent account of radiative heating and ionization of the upper planetary atmosphere, as well as related photo-chemistry, consequent expansion of the atmospheric material and its interaction with the planetary intrinsic magnetic field and stellar wind. The role of the discovered during the first period of the project exoplanetary magnetodisks will be further studied and quantified. Along with that, the global current system of the exoplanetary magnetosphere and related electrodynamical processes in the thin current sheets of the magnetodisk and magnetotail will be studied by the original methods based on the plasma kinetic theory. Significant accent will be made on possible observational manifestations of specific magnetospheric features, e.g., spectral effects produced by magnetodisk related “dead-“ and “wind-“ zones; quasi-periodic dynamic regimes of magnetodisk formation, associated particle acceleration processes and electromagnetic emissions. Implication of the modelling concepts, developed during the first period for the giant exoplanets, to the planets of smaller mass and potential habitats (e.g. Hot Neptunes, super-Earths and Earths) is planned.