Numerical investigation of kinetic turbulence in relativistic pair plasmas - I. Turbulence statistics
Numerical investigation of kinetic turbulence in relativistic pair plasmas - I. Turbulence statistics
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相对论对等离子体中运动湍流的数值研究 - I. 湍流统计
DOI：
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
M. Begelman
中科院分区：
文献类型：
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作者：
V. Zhdankin;D. Uzdensky;G. Werner;M. Begelman
我们描述了在无碰撞，磁化，相对论对等离子体驱动湍流的粒子模拟的结果。这一物理机制为研究动力学湍流的基本性质提供了一个简单的环境，并与脉冲星风、星云和天体物理喷流等高能天体物理系统有关。在本文中，我们调查的湍流波动的统计模拟晶格上的细胞高达$1024^3$，并包含高达$2 \× 10^{11}$粒子。由于在我们的模拟中没有冷却机制，湍流能量耗散在几个动力学时间内将磁化参数降低到有序统一，导致湍流运动成为亚相对论性。在发展阶段，我们的结果与磁流体动力学湍流现象学在惯性尺度上的预言一致，包括指数接近$-5/3$的幂律磁能谱，由临界平衡描述的涨落的尺度依赖各向异性，粒子密度和内能密度的对数正态分布（与4/3$绝热指数相关，如对超相对论性理想气体所预测的那样），以及不稳定性的存在。我们还提出了可能的签名的动力级联通过测量幂律谱的磁，电，和密度波动在次拉莫尔尺度。
We describe results from particle-in-cell simulations of driven turbulence in collisionless, magnetized, relativistic pair plasma. This physical regime provides a simple setting for investigating the basic properties of kinetic turbulence and is relevant for high-energy astrophysical systems such as pulsar wind nebulae and astrophysical jets. In this paper, we investigate the statistics of turbulent fluctuations in simulations on lattices of up to $1024^3$ cells and containing up to $2 \times 10^{11}$ particles. Due to the absence of a cooling mechanism in our simulations, turbulent energy dissipation reduces the magnetization parameter to order unity within a few dynamical times, causing turbulent motions to become sub-relativistic. In the developed stage, our results agree with predictions from magnetohydrodynamic turbulence phenomenology at inertial-range scales, including a power-law magnetic energy spectrum with index near $-5/3$, scale-dependent anisotropy of fluctuations described by critical balance, log-normal distributions for particle density and internal energy density (related by a $4/3$ adiabatic index, as predicted for an ultra-relativistic ideal gas), and the presence of intermittency. We also present possible signatures of a kinetic cascade by measuring power-law spectra for the magnetic, electric, and density fluctuations at sub-Larmor scales.
DOI：
10.3847/1538-4357/aa9754
发表时间：
2017-07
期刊：
The Astrophysical Journal
影响因子：
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作者：
N. Loureiro;S. Boldyrev
通讯作者：
N. Loureiro;S. Boldyrev
DOI：
10.1088/0004-637x/807/1/39
发表时间：
2014-03
期刊：
The Astrophysical Journal
影响因子：
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作者：
B. Chandran;A. Schekochihin;A. Mallet
通讯作者：
B. Chandran;A. Schekochihin;A. Mallet