Sironi Lorenzo, Plotnikov Illya, Nättilä Joonas, Beloborodov Andrei M
Department of Astronomy and Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA.
IRAP, Université de Toulouse III-Paul Sabatier, OMP, Toulouse 31400, France.
Phys Rev Lett. 2021 Jul 16;127(3):035101. doi: 10.1103/PhysRevLett.127.035101.
Relativistic magnetized shocks are a natural source of coherent emission, offering a plausible radiative mechanism for fast radio bursts (FRBs). We present first-principles 3D simulations that provide essential information for the FRB models based on shocks: the emission efficiency, spectrum, and polarization. The simulated shock propagates in an e^{±} plasma with magnetization σ>1. The measured fraction of shock energy converted to coherent radiation is ≃10^{-3}σ^{-1}, and the energy-carrying wave number of the wave spectrum is ≃4ω_{c}/c, where ω_{c} is the upstream gyrofrequency. The ratio of the O-mode and X-mode energy fluxes emitted by the shock is ≃0.4σ^{-1}. The dominance of the X mode at σ≫1 is particularly strong, approaching 100% in the spectral band around 2ω_{c}. We also provide a detailed description of the emission mechanism for both X and O modes.
相对论磁化激波是相干辐射的天然来源，为快速射电暴（FRB）提供了一种合理的辐射机制。我们展示了基于激波的FRB模型的第一性原理三维模拟，该模拟提供了发射效率、频谱和偏振等基本信息。模拟的激波在磁化强度σ>1的正负电子等离子体中传播。测量得到的激波能量转换为相干辐射的比例约为10⁻³σ⁻¹，波谱中携带能量的波数约为4ωₑ/c，其中ωₑ是上游回旋频率。激波发射的O模和X模能量通量之比约为0.4σ⁻¹。在σ≫1时，X模的主导地位尤为明显，在2ωₑ附近的频段接近100%。我们还详细描述了X模和O模的发射机制。
