Leaking Outside the Box: Kinetic Turbulence with Cosmic-Ray Escape

Fuente: arXiv
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Hauptverfasser: Gorbunov, Evgeny A., Grošelj, Daniel, Bacchini, Fabio
Format: Preprint
Veröffentlicht: 2025
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author Gorbunov, Evgeny A.
Grošelj, Daniel
Bacchini, Fabio
author_facet Gorbunov, Evgeny A.
Grošelj, Daniel
Bacchini, Fabio
contents We study particle acceleration in strongly turbulent pair plasmas using novel 3D Particle-in-Cell simulations, featuring particle injection from an external heat bath and diffusive escape. We demonstrate the formation of steady-state, nonthermal particle distributions with maximum energies reaching the Hillas limit. The steady state is characterized by the equilibration of plasma kinetic and magnetic pressures, which imposes upper limits on the acceleration rate. With growing cold plasma magnetization $σ_0$, nonthermal power-law spectra become harder, and the fraction of energy channeled into escaping cosmic rays increases. At $σ_0 \gtrsim 1$, the escaping cosmic rays amount to more than 50% of the dissipated energy. Our method allows for kinetic studies of particle acceleration under steady-state conditions, with applications to a variety of astrophysical systems.
format Preprint
id arxiv_https___arxiv_org_abs_2503_03820
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Leaking Outside the Box: Kinetic Turbulence with Cosmic-Ray Escape
Gorbunov, Evgeny A.
Grošelj, Daniel
Bacchini, Fabio
High Energy Astrophysical Phenomena
Plasma Physics
We study particle acceleration in strongly turbulent pair plasmas using novel 3D Particle-in-Cell simulations, featuring particle injection from an external heat bath and diffusive escape. We demonstrate the formation of steady-state, nonthermal particle distributions with maximum energies reaching the Hillas limit. The steady state is characterized by the equilibration of plasma kinetic and magnetic pressures, which imposes upper limits on the acceleration rate. With growing cold plasma magnetization $σ_0$, nonthermal power-law spectra become harder, and the fraction of energy channeled into escaping cosmic rays increases. At $σ_0 \gtrsim 1$, the escaping cosmic rays amount to more than 50% of the dissipated energy. Our method allows for kinetic studies of particle acceleration under steady-state conditions, with applications to a variety of astrophysical systems.
title Leaking Outside the Box: Kinetic Turbulence with Cosmic-Ray Escape
topic High Energy Astrophysical Phenomena
Plasma Physics
url https://arxiv.org/abs/2503.03820