Distribution of Velocity Gradient Orientations: Mapping Magnetization with the Velocity Gradient Technique
Distribution of Velocity Gradient Orientations: Mapping Magnetization with the Velocity Gradient Technique
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DOI：
10.3847/1538-4357/aad7ff
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发表时间：
2018-02
期刊：
影响因子：
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通讯作者：
A. Lazarian;K. Yuen;K. Ho;Jun-De Chen;Victor Lazarian;Zekun Lu;Zekun Lu;Bo Yang;Yue Hu;Yue Hu
中科院分区：
文献类型：
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作者：
A. Lazarian;K. Yuen;K. Ho;Jun-De Chen;Victor Lazarian;Zekun Lu;Zekun Lu;Bo Yang;Yue Hu;Yue Hu
速度梯度技术（VGT）的最新发展表明，速度梯度提供了一个可靠的跟踪湍流等离子体中的磁场方向。在本文中，我们探讨速度梯度测量星际介质的磁化强度的能力。我们表明，速度梯度方向的分布提供了一个可靠的估计介质的磁化强度。特别是，我们确定的范围内的Alfvénic马赫数MA和性能的速度梯度分布之间的关系，即，与速度梯度方向的分散体以及与振幅的峰底比。我们将我们的技术应用到一个选定的GALFA-H i区域，并发现结果与MA的预期行为一致。使用3D磁流体动力学模拟，我们成功地比较了结果与我们的新措施的磁化强度是基于分散的星光偏振。我们证明，结合速度分散沿着视线方向，我们的技术是能够提供的磁场强度。这项新技术开辟了一种使用其他梯度测量方法（如同步加速器强度梯度和同步加速器极化梯度）来测量磁化强度的方法。
Recent developments of the velocity gradient technique (VGT) show that the velocity gradients provide a reliable tracing of the magnetic field direction in turbulent plasmas. In this paper, we explore the ability of velocity gradients to measure the magnetization of the interstellar medium. We demonstrate that the distribution of velocity gradient orientations provides a reliable estimation of the magnetization of the media. In particular, we determine the relation between Alfvénic Mach number MA in the range of and properties of the velocity gradient distribution, namely, with the dispersion of velocity gradient orientation as well as with the peak-to-base ratio of the amplitudes. We apply our technique to a selected GALFA-H i region and find the results consistent with the expected behavior of MA. Using 3D magnetohydrodynamic simulations, we successfully compare the results with our new measure of magnetization that is based on the dispersion of starlight polarization. We demonstrate that combined with the velocity dispersion along the line-of-sight direction, our technique is capable of delivering the magnetic field strength. The new technique opens a way to measure magnetization using other gradient measures, such as synchrotron intensity gradients and synchrotron polarization gradients.