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arXiv · 2307.00876

Electron slingshot acceleration in relativistic preturbulent shocks explored via emitted photon polarization

Zheng Gong·Xiaofei Shen·Karen Z. Hatsagortsyan·Christoph H. Keitel
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Abstract

Transient electron dynamics near the interface of counterstreaming plasmas at the onset of a relativistic collisionless shock (RCS) is investigated using particle-in-cell simulations. We identify a slingshot-like injection process induced by the drifting electric field sustained by the flowing focus of backwards-moving electrons, which is distinct from the well-known stochastic acceleration. The flowing focus signifies the plasma kinetic transition from a preturbulent laminar motion to a chaotic turbulence. We find a characteristic correlation between the electron dynamics in the slingshot acceleration and the photon emission features. In particular, the integrated radiation from the RCS exhibits a counterintuitive non-monotonic dependence of the photon polarization degree on the photon energy, which originates from a polarization degradation of relatively high-energy photons emitted by the slingshot-injected electrons. Our results demonstrate the potential of photon polarization as an essential information source in exploring intricate transient dynamics in RCSs with relevance for earth-based plasma and astrophysical scenarios.

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Zheng Gong, Xiaofei Shen, Karen Z. Hatsagortsyan, Christoph H. Keitel. 2023-07-03. Electron slingshot acceleration in relativistic preturbulent shocks explored via emitted photon polarization. https://doi.org/10.1103/physrevlett.131.225101

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