arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1402.7167astro-ph.GA
收藏

湍流热电离介质中的磁场和法拉第旋转测量

Magnetic Field and Faraday Rotation Measure in the Turbulent Warm Ionized Medium

Qingwen Wu, Jongsoo Kim, Dongsu Ryu

摘要:

Wu等人(2009年)提出了一个经验关系式,即在均方根音速马赫数为$M_s \simeq 1$的湍流介质中,沿视线(LOS)的磁场强度与法拉第旋转测量(RM)分布的色散之间的关系。在本文中,我们扩展的工作,纳入马赫数的依赖。介质与$\sim 0.5 < M_s < \sim 2$被认为是覆盖马赫数范围内的温暖电离介质(WIM)的银河系。三维,磁流体动力学等温湍流模拟与螺线管强迫。我们提出了一个新的关系LOS磁场强度,RM分布的色散,和马赫数,近似代表的关系Alfvénic扰动。此外,我们还提出了马赫数与排放量(EM)对数正态分布的离散度之间的关系,它基本上是马赫数与密度离散度之间的关系。该关系可用于快速粗略估计湍流WIM中的LOS磁场强度。

英文摘要:

Wu et al. (2009) suggested an empirical relation between the magnetic field strength along the line of sight (LOS) and the dispersion of Faraday rotation measure (RM) distribution in turbulent media with root-mean-square sonic Mach number $M_s \simeq 1$. In this paper, we extend the work by incorporating the Mach number dependence. Media with $\sim 0.5 < M_s < \sim 2$ are considered to cover the Mach number range of the warm ionized medium (WIM) of our Galaxy. Three-dimensional, magnetohydrodynamic isothermal turbulence simulations with solenoidal forcing are used. We suggest a new relation among the LOS magnetic field strength, the dispersion of RM distribution, and the Mach number, which approximately represents the relation for Alfvénic perturbations. In addition, we suggest a relation between the Mach number and the dispersion of log-normal distribution of emission measure (EM), which is basically the relation for the Mach number and the density dispersion. The relations could be used for a quick and rough estimation of the LOS magnetic field strength in the turbulent WIM.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑