Relativistic Magnetic Reconnection in Electron–Positron–Proton Plasmas: Implications for Jets of Active Galactic Nuclei
Relativistic Magnetic Reconnection in Electron–Positron–Proton Plasmas: Implications for Jets of Active Galactic Nuclei
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DOI：
10.3847/1538-4357/ab287a
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发表时间：
2019-06
期刊：
影响因子：
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通讯作者：
M. Petropoulou;L. Sironi;A. Spitkovsky;D. Giannios
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作者：
M. Petropoulou;L. Sironi;A. Spitkovsky;D. Giannios
磁重联常被用来解释相对论性喷流的非热辐射，包括活动星系核（agn）的喷流。由于AGN喷流的等离子体成分在很大程度上是未知的，我们研究了电子-正电子-质子（对质子）等离子体的未探索状态下的重连接，并进行了大规模二维粒子在细胞内的模拟。我们涵盖了各种等离子体磁化（σ = 1,3和10）和电子温度（）的不同值对多重度（轻子-质子数比κ = 1 - 199）的广泛范围。我们重点研究了重联后的能量分配和轻子能谱与热对等离子体磁化（即磁焓密度与对焓密度之比）的关系。我们发现，重联后的能量在磁场、电子对和质子之间大致平均地分布。我们经验地发现，重连接后区域的平均轻子洛伦兹因子依赖于σ， Θe和as，当σ≥1时。重联后轻子能量分布的高能部分可以用幂律来描述，其斜率主要由k≤3-6控制，在高磁化强度下幂律更硬。我们最后表明，在多重度κ ~ 1-20、磁化强度σ ~ 1-10和温度Θe ~ 1-10的对质子等离子体中，重连接导致粒子幂律斜率和平均电子洛伦兹因子与AGN射流发射轻子模型中推断的结果一致。
Magnetic reconnection is often invoked to explain the nonthermal radiation of relativistic outflows, including jets of active galactic nuclei (AGNs). Motivated by the largely unknown plasma composition of AGN jets, we study reconnection in the unexplored regime of electron–positron–proton (pair-proton) plasmas with large-scale two-dimensional particle-in-cell simulations. We cover a wide range of pair multiplicities (lepton-to-proton number ratio κ = 1–199) for different values of the all-species plasma magnetization (σ = 1, 3, and 10) and electron temperature ( ). We focus on the dependence of the post-reconnection energy partition and lepton energy spectra on the hot pair plasma magnetization (i.e., the ratio of magnetic to pair enthalpy densities). We find that the post-reconnection energy is shared roughly equally between magnetic fields, pairs, and protons for ≳ 3. We empirically find that the mean lepton Lorentz factor in the post-reconnection region depends on σ, Θe, and as , for σ ≥ 1. The high-energy part of the post-reconnection lepton energy distributions can be described by a power law, whose slope is mainly controlled by for κ ≳ 3–6, with harder power laws obtained for higher magnetizations. We finally show that reconnection in pair-proton plasmas with multiplicities κ ∼ 1–20, magnetizations σ ∼ 1–10, and temperatures Θe ∼ 1–10 results in particle power-law slopes and average electron Lorentz factors that are consistent with those inferred in leptonic models of AGN jet emission.