论文标题
弱压缩的泰勒绿色涡流中的磁化腐烂湍流
Magnetized Decaying Turbulence in the Weakly Compressible Taylor-Green Vortex
论文作者
论文摘要
磁流失动力的湍流影响陆生和天体物理等离子体。必须更好地理解磁化湍流的特性，以更准确地表征这些系统。这项工作为可压缩的泰勒绿色涡流提供了理想的MHD仿真，在一系列初始亚音马赫数和磁场强度范围内。我们发现，无论最初的场强度如何，在最多几个动态时间之后，磁能在所有尺度上都在动能上占主导地位。随着时间的推移，动能光谱的光谱指数比$ k^{ - 5/3} $浅，并且通常会波动。使用壳壳的能量传递分析框架，我们发现磁场有助于大量的能量通量，并且动力学能量级联受到抑制。此外，我们观察到通过磁张力从大型动能到中间和小规模的磁能的非局部能量转移。我们得出的结论是，即使在间歇性或奇异驱动的弱磁化系统中，磁场的动态效应也无法忽略。
Magnetohydrodynamic turbulence affects both terrestrial and astrophysical plasmas. The properties of magnetized turbulence must be better understood to more accurately characterize these systems. This work presents ideal MHD simulations of the compressible Taylor-Green vortex under a range of initial sub-sonic Mach numbers and magnetic field strengths. We find that regardless of the initial field strength, the magnetic energy becomes dominant over the kinetic energy on all scales after at most several dynamical times. The spectral indices of the kinetic and magnetic energy spectra become shallower than $k^{-5/3}$ over time and generally fluctuate. Using a shell-to-shell energy transfer analysis framework, we find that the magnetic fields facilitate a significant amount of the energy flux and that the kinetic energy cascade is suppressed. Moreover, we observe nonlocal energy transfer from the large scale kinetic energy to intermediate and small scale magnetic energy via magnetic tension. We conclude that even in intermittently or singularly driven weakly magnetized systems, the dynamical effects of magnetic fields cannot be neglected.
