论文标题
可压缩MHD湍流中的各向异性：探测磁场和测量磁化
Anisotropies in Compressible MHD Turbulence: Probing Magnetic Fields and Measuring Magnetization
论文作者
论文摘要
众所周知，在星际介质（ISM）中探测磁场是具有挑战性的。由磁性水力学（MHD）的湍流和湍流各向异性的现代理论的动机，我们引入了结构功能分析（SFA），作为测量磁场方向并估算磁化的新方法。我们通过局部和全局参考帧中的二阶结构函数分析了三维压缩MHD模拟中湍流速度的统计。在磁能大于湍流能量的磁能的下湍流中，在垂直方向和平行于磁场的方向上测得的湍流速度的SFA可能显着不同。他们的比率对Alfven Mach Number $ M_A $具有幂律的依赖，该$ M_A $与磁场强度成反比。我们证明，湍流速度的各向异性结构函数可用于估计磁场的方向和强度。使用使用不同示踪剂测量的湍流速度，我们的方法通常可以应用于多相星际介质中的磁场。
Probing magnetic fields in the interstellar medium (ISM) is notoriously challenging. Motivated by the modern theories of magnetohydrodynamic (MHD) turbulence and turbulence anisotropy, we introduce the Structure-Function Analysis (SFA) as a new approach to measure the magnetic field orientation and estimate the magnetization. We analyze the statistics of turbulent velocities in three-dimensional compressible MHD simulations through the second-order structure functions in both local and global reference frames. In the sub-Alfvenic turbulence with the magnetic energy larger than the turbulent energy, the SFA of turbulent velocities measured in the directions perpendicular and parallel to the magnetic field can be significantly different. Their ratio has a power-law dependence on the Alfven Mach number $M_A$, which is inversely proportional to the magnetic field strength. We demonstrate that the anisotropic structure functions of turbulent velocities can be used to estimate both the orientation and strength of magnetic fields. With turbulent velocities measured using different tracers, our approach can be generally applied to probing the magnetic fields in the multi-phase interstellar medium.
