Vol. 633
Sect. 10. Planets and planetary systems

Magnetohydrodynamic simulations of a Uranus-at-equinox type rotating magnetosphere

by L. Griton & F. Pantellini 2020, A&A, 633, A87 alt

Any solar system example provides a good departure point for understanding the physical processes and environments in the vastly diverse realm of exoplanetary systems. This is especially true for magnetospheres and interplanetary interactions with planetary magnetic fields. The Solar System example of Uranus is a remarkable oblique rotator whose magnetosphere shows long-time presentations of equatorial and polar-cusp to incoming supersonic flow. The authors study magnetohydrodynamic (MHD) simulations of an orthogonally-oriented planetary magnetosphere with incident unmagnetized and magnetized stellar wind flows. The magnetized wind induces reconnection and disconnection events as well as field distortions, some of which are more extreme than modeled for aligned fields. The neutral case shows field line distortions that produce puffs and tailward expulsions, especially in the rapidly rotting planetary model. While schematic at present, this paper demonstrates the tremendous promise of more physically realistic and computationally refined simulations to make significant observational predictions (e.g., auroral activity, nonthermal emission, and limits to atmospheric escape).