论文标题
使用双光谱研究星际湍流驾驶量表
Studying Interstellar Turbulence Driving Scales using the Bispectrum
论文作者
论文摘要
我们证明了双方三分相关函数的双光谱效用，用于研究星际介质中磁性水力学（MHD）湍流的驱动尺度。我们通过实施并行的蒙特卡洛直接测量方法来计算双光谱，我们已公开可用。在以前的作品中，双光谱已用于识别非线性缩放相关性，并在诸如功率谱之类的较低阶段中打破脱落。我们发现，两种统计量的相关统计量，可测量傅立叶模式的相位耦合，并使用密度和柱密度字段识别湍流驱动尺度。特别是，它表明驾驶量表是相耦合到湍流级联中存在的量表。我们还发现，与纯净流体动力学相比，大尺度上有序的磁场的存在会增强相位耦合。因此，我们建议双光谱和双晶格作为寻找MHD湍流中波相互作用的非本地性的工具。
We demonstrate the utility of the bispectrum, the Fourier three-point correlation function, for studying driving scales of magnetohydrodynamic (MHD) turbulence in the interstellar medium. We calculate the bispectrum by implementing a parallelized Monte Carlo direct measurement method, which we have made publicly available. In previous works, the bispectrum has been used to identify non-linear scaling correlations and break degeneracies in lower-order statistics like the power spectrum. We find that the bicoherence, a related statistic which measures phase coupling of Fourier modes, identifies turbulence driving scales using density and column density fields. In particular, it shows that the driving scale is phase-coupled to scales present in the turbulent cascade. We also find that the presence of an ordered magnetic field at large-scales enhances phase coupling as compared to a pure hydrodynamic case. We therefore suggest the bispectrum and bicoherence as tools for searching for non-locality for wave interactions in MHD turbulence.
