From the Sun–Earth System to Exoplanetary and Astrophysical Plasmas

Suleiman Baraka (National Institute of Aerospace)

February 02, 2026

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Abstract: Kinetic modelling offers a unique capability to resolve plasma processes that are inherently inaccessible to fluid or hybrid descriptions. This is particularly critical for cold plasma populations, whose low energies and non-Maxwellian features are often poorly sampled or entirely missed by in situ spacecraft measurements. In this talk, I present the development and applications of a Particle-in-Cell (PIC) code that has demonstrated broad versatility across a wide range of plasma environments. Originally developed to study solar wind magnetosphere interactions, the code has since evolved into a flexible kinetic framework capable of capturing diverse plasma regimes. It has been successfully applied to simulations of magnetosphere ionosphere coupling, plasma-sheet interactions with the lunar surface, plasma interactions with Jovian and Saturnian moons, and stellar-wind interactions with close-in exoplanets embedded within their host stars coronae. These applications naturally intersect with several research directions pursued at the Canadian Institute for Theoretical Astrophysics (CITA), particularly in multi-scale plasma dynamics, star planet interactions, and the kinetic foundations of astrophysical environments. The model employs macro-particles representing large ensembles of ions and electrons, while retaining a fully kinetic, electromagnetic formulation. This general framework enables scalable applications beyond planetary systems, offering a pathway toward modeling larger astrophysical plasmas, including star planet coupling and, in principle, galactic-scale environments. I will highlight key physical insights enabled by this approach and discuss its relevance for future multi-scale plasma investigations.