Interaction between the turbulent solar wind and a planetary magnetosphere: A 2D comet example

E. Behar (1, 2, 3) , P. Henri (4, 2, 3)

1 IRF - Swedish Institute of Space Physics [Kiruna]
2 LAGRANGE - Joseph Louis LAGRANGE
3 OCA - Observatoire de la Côte d'Azur
4 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

Context. Using the newly developed code Menura , we present the first global picture of the interaction between a turbulent solar wind and a planetary obstacle in our solar system, namely a comet. Aims. This first publication sheds light on the macroscopic effect of the upstream solar wind turbulence on the induced magnetosphere of a comet. Methods. Using a hybrid particle-in-cell simulation code, we modelled a medium activity comet using turbulent and laminar solar wind input, for a direct comparison between the two regimes. Results. We show how the turbulent characteristics of the solar wind lead to a smaller obstacle size. We then present how the upstream turbulent structures, traced by the perpendicular magnetic field fluctuations absent in the laminar case, self-consistently drape and pile up around the denser inner coma, forming intense plasmoids downstream of the nucleus, pulling away dense cometary ion bubbles. This pseudo-periodic erosion phenomenon re-channels the global cometary ion escape; as a result, the innermost coma is found to be on average 45% less dense in the turbulent case than predicted by simulating a laminar upstream flow.

Domaines: Planète et Univers [physics]

E. Behar, P. Henri. Interaction between the turbulent solar wind and a planetary magnetosphere: A 2D comet example. Astronomy and Astrophysics - A&A, 2023, 671, pp.A144. ⟨10.1051/0004-6361/202244455⟩. ⟨insu-04060105⟩