Two cases of convecting structure in the slow solar wind turbulence

The slow solar wind turbulence has recently been considered as fully evolved turbulence which can be described by critical balance theory. However, here we present two cases of convecting structure that support a different understanding. By using the measurements from WIND spacecraft in the slow solar wind, we find that Elsässer variables Z ± of these two cases do not represent inward and outward Alfvén waves, but are determined mainly by the magnetic variations, including tangentially varying structures. We then propose that the slow wind turbulence may be composed of convecting magnetic-field tangential and directional turnings, as well as current sheets, which may be considered as left-over fossils from Kolmogorov fluid turbulence. The fluid kinetic energy has been damped out, and the remaining magnetic fluctuations thus tend to become force-free structures.