Fraction of Energy Carried by Coherent Structures in the Turbulent Cascade in the Solar Wind

Turbulence is prevalent in astrophysical plasma flows. Both wave–wave interactions and coherent structures offer mechanisms to mediate turbulent cascades. Solar Orbiter in situ satellite observations of plasma turbulence in the solar wind are used to determine the percentage of the power in the turbulent cascade carried by coherent structures, and its anisotropy. In the inertial range of magnetohydrodynamic turbulence, this percentage increases with increasing frequency, up to a maximum of ∼50% just below the scale break where the kinetic range begins. The percentage then decreases with increasing frequency in the kinetic range. The behavior is most ordered at solar distances <0.4 au with evidence of two subranges in the inertial range at distances beyond this. The energy carried in coherent structures may ultimately heat the solar wind.