Turbulence versus Fire-hose Instabilities: 3D Hybrid Expanding Box Simulations
Turbulence versus Fire-hose Instabilities: 3D Hybrid Expanding Box Simulations
复制标题
湍流与消防水带不稳定性：3D 混合膨胀箱模拟
DOI：
10.3847/1538-4357/ab3e01
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
E. Papini
中科院分区：
文献类型：
--
作者：
P. Hellinger;L. Matteini;S. Landi;L. Franci;A. Verdini;E. Papini
使用三维混合膨胀箱模拟研究了缓慢膨胀等离子体中衰减等离子体湍流与质子消防水带不稳定性之间的关系。我们沿径向施加初始环境磁场，并从具有零交叉螺旋度的大尺度、线性极化、随机相位阿尔芬涨落的各向同性谱开始。湍流级联迅速发展并导致弱质子加热，不足以克服膨胀驱动的垂直冷却。等离子体系统最终驱动平行和倾斜的消防水带不稳定性，产生准单色波包，从而降低质子温度各向异性。消防水带波活动具有低振幅，波矢量相对于湍流级联主导区域之外的环境磁场准平行/倾斜，并且仅在相对于环境磁场准平行/倾斜的方向上获取的一维功率谱中是可辨别的；在准垂直角度，波活动被湍流背景隐藏。这些波部分被质子重新吸收，部分耦合并参与湍流级联。它们的存在降低了峰度（间歇性的度量）和香农熵，但增加了磁涨落的詹森-香农复杂性；这些变化相对于环境磁场来说是微弱且各向异性的，目前尚不清楚它们是否可以用来间接辨别不稳定驱动波的存在。
The relationship between a decaying plasma turbulence and proton fire hose instabilities in a slowly expanding plasma is investigated using three-dimensional hybrid expanding box simulations. We impose an initial ambient magnetic field along the radial direction, and we start with an isotropic spectrum of large-scale, linearly polarized, random-phase Alfvénic fluctuations with zero cross-helicity. A turbulent cascade rapidly develops and leads to a weak proton heating that is not sufficient to overcome the expansion-driven perpendicular cooling. The plasma system eventually drives the parallel and oblique fire hose instabilities that generate quasi-monochromatic wave packets that reduce the proton temperature anisotropy. The fire hose wave activity has a low amplitude with wave vectors quasi-parallel/oblique with respect to the ambient magnetic field outside of the region dominated by the turbulent cascade and is discernible in one-dimensional power spectra taken only in the direction quasi-parallel/oblique with respect to the ambient magnetic field; at quasi-perpendicular angles the wave activity is hidden by the turbulent background. These waves are partly reabsorbed by protons and partly couple to and participate in the turbulent cascade. Their presence reduces kurtosis, a measure of intermittency, and the Shannon entropy, but increases the Jensen–Shannon complexity of magnetic fluctuations; these changes are weak and anisotropic with respect to the ambient magnetic field and it is not clear if they can be used to indirectly discern the presence of instability-driven waves.
使用混合代码 CAMELIA 进行太阳风湍流的三维模拟
DOI：
10.1088/1742-6596/1031/1/012002
发表时间：
2018
期刊：
Conference Series
影响因子：
--
作者：
Franci L
通讯作者：
Franci L
影响因子：
6.5
作者：
D. Stansby;D. Perrone;L. Matteini;T. Horbury;C. Salem
通讯作者：
D. Stansby;D. Perrone;L. Matteini;T. Horbury;C. Salem
影响因子：
4.9
作者：
Arzamasskiy, Lev;Kunz, Matthew W.;Quataert, Eliot
通讯作者：
Quataert, Eliot