NUMERICAL SIMULATIONS OF IMBALANCED STRONG MAGNETOHYDRODYNAMIC TURBULENCE
NUMERICAL SIMULATIONS OF IMBALANCED STRONG MAGNETOHYDRODYNAMIC TURBULENCE
复制标题
不平衡强磁流体湍流的数值模拟
DOI：
10.1088/2041-8205/710/1/l63
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
S. Boldyrev
中科院分区：
文献类型：
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作者：
J. C. Perez;S. Boldyrev
磁流体动力学（MHD）被用来解决各种天体物理系统中的湍流波动。自然界中的MHD湍流通常是各向异性和不平衡的，因为沿背景磁场沿着相反方向运动的阿尔夫文涨落携带不相等的能量。这项工作制定了具体的要求，有效的数值模拟强不平衡MHD湍流与引导场B0。高分辨率的模拟，然后进行，他们建议，对向传播的阿尔文模式的频谱没有不同的平衡的情况下，而它们的振幅和相应的能量级联率显着的不平衡的影响。进一步提出，不平衡越强，数值模拟中所需的磁雷诺数越大，以便正确地再现湍流谱。这可以解释目前数值模拟和观测不平衡MHD湍流之间的差异。
Magnetohydrodynamics (MHD) is invoked to address turbulent fluctuations in a variety of astrophysical systems. MHD turbulence in nature is often anisotropic and imbalanced, in that Alfvénic fluctuations moving in opposite directions along the background magnetic field carry unequal energies. This work formulates specific requirements for effective numerical simulations of strong imbalanced MHD turbulence with a guide field B0. High-resolution simulations are then performed and they suggest that the spectra of the counterpropagating Alfvén modes do not differ from the balanced case, while their amplitudes and the corresponding rates of energy cascades are significantly affected by the imbalance. It is further proposed that the stronger the imbalance the larger the magnetic Reynolds number that is required in numerical simulations in order to correctly reproduce the turbulence spectrum. This may explain current discrepancies among numerical simulations and observations of imbalanced MHD turbulence.