Linear stability analysis of magnetized relativistic jets: the non-rotating case
Linear stability analysis of magnetized relativistic jets: the non-rotating case
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磁化相对论射流的线性稳定性分析：非旋转情况
DOI：
10.1093/mnras/stt1225
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发表时间：
2013
影响因子：
4.8
通讯作者：
Andrea Mignone
中科院分区：
文献类型：
--
作者：
G. Bodo;G. Mamatsashvili;P. Rossi;Andrea Mignone
本文在零热压近似下对磁化相对论非旋转圆柱流的稳定性进行了线性分析，|M| = 1模式。我们发现有两种模式的不稳定性：Kelvin-Helmholtz和电流驱动。Kelvin-Helmholtz模式被发现在低磁化强度和它的增长率依赖于很弱的间距参数。电流驱动模式被发现在高的磁化强度和增长率的值和波数的最大值增加，因为我们减少的间距参数。在相对论区域中，电流驱动模式分裂成两个分支，高波数处的分支的特征在于本征函数集中在射流核心中，而低波数处的分支的特征在于本征函数延伸到射流速度剪切区域之外。天体物理喷流的形成和传播受到等离子体不稳定性的强烈影响，因此，等离子体不稳定性的研究对于理解其动力学及其相关现象学具有根本的重要性。在喷流中有几种可能的不同类型的不稳定性，其中研究最多的是由喷流和周围介质之间的速度剪切驱动的Kelvin-Helmholtz不稳定性（KHI）和与纵向电流相关的电流驱动不稳定性（CDI），因此与磁场的环形分量有关。由于喷流加速和准直的最有希望的模型涉及到磁场的存在，其足点锚定在旋转物体（吸积盘或旋转的星星或黑洞）上，因此环向场分量的存在是一个不确定因素。
We perform a linear analysis of the stability of a magnetized relativistic nonrotating cylindrical flow in the aproximation of zero thermal pressure, considering only the |m| = 1 mode. We find that there are two modes of instability: Kelvin-Helmholtz and current driven. The Kelvin-Helmholtz mode is found at low magnetizations and its growth rate depends very weakly on the pitch parameter. The current driven modes are found at high magnetizations and the value of the growth rate and the wavenumber of the maximum increase as we decrease the pitch parameter. In the relativistic regime the current driven mode is splitted in two branches, the branch at high wavenumbers is characterized by the eigenfunction concentrated in the jet core, the branch at low wavenumbers is instead characterized by the eigenfunction that extends outside the jet velocity shear region. The formation and propagation of astrophysical jets are strongly affected by plasma instabilities, whose study is therefore of fundamental importance for understanding their dynamics and their associated phenomenology. In jets there are several possible different kinds of instability, among them the most studied are the Kelvin-Helmholtz instability (KHI) driven by the velocity shear between the jet and the ambient medium and the current driven instability (CDI) associated with a longitudinal current and therefore with the toroidal component of magnetic field. Since the most promising models for the acceleration and collimation of jets involve the presence of a magnetic field with footpoints anchored to a rotating object (an accretion disk or a spinning star or black hole), the presence of a toroidal field component is a