Séminaire des doctorants Orléans
Anwar El Rhirhayi: Galactic dynamics and Kinetic Theory of Stellar Systems near the marginal stability regimeAnwar El Rhirhayi (IDP-Orléans)
Thursday 13 February 2025 10:30 - IDP-Orléans - Salle de séminaire
Résumé :
The dynamics of self-gravitating systems, including spiral and elliptical galaxies and globular clusters, are described by a kinetic theory that must account for a range of processes and characteristics, making their behavior complex to model. Due to the long-range nature of gravity, collective effects arise, amplifying the system's response to perturbations and influencing its dynamics over very long timescales. The current kinetic theory, known as the Balescu-–Lenard (BL) theory, exhibits some divergences because it cannot accurately describe scenarios where system-wide self-coherent perturbations (known as Landau modes) damp very slowly and persist long enough to affect the system's long-term dynamics. In these cases, the system is referred to as marginally stable. In this presentation we will see how to regularize the marginally stable BL theory to include the effects of Landau modes in the secular evolution of stellar systems.
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