Erlangen 2026 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 16: Poster Session Plasma Physics

P 16.109: Poster

Donnerstag, 19. März 2026, 13:45–15:45, Redoutensaal

energy dissipation in collisionless shocks: MMS observations — •Valentina Villaflor, Artem Bohdan, and Frank Jenko — Max Planck Institute for Plasma Physics, Garching, Germany

Collisionless shocks play a key role in space and astrophysical plasmas, enabling the conversion of large-scale kinetic energy into heat and non-thermal particle populations without relying on binary Coulomb collisions. Instead, these shocks are sustained by collective effects such as wave-particle interactions that are inherently kinetic and nonlinear. Despite significant observational and theoretical efforts, the precise mechanisms of energy dissipation in collisionless shocks remain debated. While it is widely accepted that dissipation occurs within the shock ramp, observations have shown that energy conversion may also extend involving other shock structures.

We analyze high-resolution measurements from the Magnetospheric Multiscale (MMS) mission across multiple quasi-perpendicular bow shock crossings. We quantify energy contribution of different particle species within a vicinity of the shock ramp to analyze energy transfer among electrons, ions. By correcting the measured ion and electron distribution functions for instrumental effects, we isolate the energy contributions of each species and examine how they vary throughout the shock structure. We calculate the theoretically expected values for thermal energy from mass conservation principles and Rankine-Hugoniot conditions to analyze the observed deviation from adiabatic behavior in collisionless shocks. Finally, we discuss how energy transfer between species depends on various shock parameters.

Keywords: collisionless shocks; energy dissipation; kinetic plasma processes; electron–ion energy transfer; non-adiabatic heating