Göttingen 2025 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 10: Poster Session I

P 10.37: Poster

Dienstag, 1. April 2025, 16:15–18:15, ZHG Foyer 1. OG

Understanding the Role of Plasma Instabilities in Blazar-Induced Pair Beams: Laboratory Simulations and Astrophysical Implications — •Suman Dey and Günter Sigl — II. Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany

The interaction of TeV photons from blazars with the extragalactic background produces a relativistic beam of electron-positron pairs streaming through the intergalactic medium, producing a cascade through up-scattering low-energy photons. Plasma instability is considered one of the underlying energy-loss processes of the beams. We employed particle-in-cell (PIC) simulations to study the plasma instabilities of ultra-relativistic pair beams propagating in a denser background plasma, using the parameters designed to replicate astrophysical jets under laboratory conditions. We have investigated the parameter regime where the electromagnetic modes are suppressed, aligning with the physically relevant criteria of Blazar-induced beams. We have used an astrophysically realistic non-Maxwellian distribution for the beam particles, improving upon previous studies. We investigated the interplay between the magnetic field forming from localized currents and transverse beam momentum spread. We calculated the physical limit of density contrast at which the beam achieves optimal suppression of electromagnetic instabilities in laboratory experiments. We extrapolated the non-linear feedback of instability where the beam is energetically broadened. We observed that the instability generates a negligible angular broadening for Blazar-Induced beams.

Keywords: astroparticle physics; instabilities; plasmas; gamma-rays: general; methods: numerical