Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom.
Phys Rev Lett. 2009 Dec 11;103(24):241101. doi: 10.1103/PhysRevLett.103.241101.
Extended or generalized similarity is a ubiquitous but not well understood feature of turbulence that is realized over a finite range of scales. The ULYSSES spacecraft solar polar passes at solar minimum provide in situ observations of evolving anisotropic magnetohydrodynamic turbulence in the solar wind under ideal conditions of fast quiet flow. We find a single generalized scaling function characterizes this finite range turbulence and is insensitive to plasma conditions. The recent unusually inactive solar minimum--with turbulent fluctuations down by a factor of approximately 2 in power--provides a test of this invariance.
广义相似性是湍流的一个普遍但尚未被很好理解的特征，它在有限的尺度范围内实现。在太阳风的快速宁静流动的理想条件下，“尤利西斯”号宇宙飞船在太阳极区的飞越提供了各向异性磁流体力学湍流的演化的现场观测。我们发现，一个单一的广义标度函数可以描述这个有限范围的湍流，并且对等离子体条件不敏感。最近异常不活跃的太阳极小期——功率波动约下降了 2 倍——为这种不变性提供了一个检验。
