Striped Jets in Post–Neutron Star Merger Systems
Striped Jets in Post–Neutron Star Merger Systems
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DOI：
10.3847/1538-4357/ace894
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发表时间：
2022-12
期刊：
影响因子：
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通讯作者：
E. Kaufman;I. Christie;A. Lalakos;A. Tchekhovskoy;D. Giannios
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文献类型：
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作者：
E. Kaufman;I. Christie;A. Lalakos;A. Tchekhovskoy;D. Giannios
在相对论喷流中，引用磁重联作为粒子加速机制的模型通常采用喷流内的渐变能量耗散轮廓。然而，这样的轮廓还没有在第一性原理模拟中重现。在这里，我们对中子星合并后的盘进行了一套3D广义相对论磁流体动力学模拟，初始磁场为纯环形磁场。我们探索了微观物理(例如，核复合、中微子发射)和系统参数(例如，盘质量)的变化。在我们所有的模拟中，我们都发现了磁条喷流的形成。这些条纹是由吸积盘中产生的极向磁通极性的反转造成的。模拟表明，条纹持续时间、τ和功率的分布变化很大，<PΦ>。我们发现，质量越大的盘产生的条纹越强，其中最强的条纹在Φ>∼20ms时达到<P−1049erg Sτ∼1。条带的磁性重联所产生的能量和变化性与在短时伽马射线暴中推断的结果一致。我们发现，累积能量的耗散分布在径向距离z和τ上大致都是幂函数，斜率在∼1.7-3的范围内；质量越大的圆盘表现出更大的斜率。
Models invoking magnetic reconnection as the particle acceleration mechanism within relativistic jets often adopt a gradual energy dissipation profile within the jet. However, such a profile has yet to be reproduced in first-principles simulations. Here we perform a suite of 3D general relativistic magnetohydrodynamic simulations of post–neutron star merger disks with an initially purely toroidal magnetic field. We explore the variations in both the microphysics (e.g., nuclear recombination, neutrino emission) and system parameters (e.g, disk mass). In all of our simulations, we find the formation of magnetically striped jets. The stripes result from the reversals in the poloidal magnetic flux polarity generated in the accretion disk. The simulations display large variations in the distributions of stripe duration, τ, and power, 〈P Φ〉. We find that more massive disks produce more powerful stripes, the most powerful of which reaches 〈P Φ〉 ∼ 1049 erg s−1 at τ ∼ 20 ms. The power and variability that result from the magnetic reconnection of the stripes agree with those inferred in short-duration gamma-ray bursts. We find that the dissipation profile of the cumulative energy is roughly a power law in both radial distance, z, and τ, with a slope in the range of ∼1.7–3; more massive disks display larger slopes.