Generalized Similarity in Finite Range Solar Wind Magnetohydrodynamic Turbulence

Abstract

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 ∼2 in power—provides a test of this invariance.