Turbulent cascade and energy transfer rate in a solar coronal mass ejection

TL;DR

This study analyzes turbulence properties and energy transfer rates in a solar coronal mass ejection, revealing how turbulence develops and persists across different regions, influenced by shock interactions and magnetic fluctuations.

Contribution

It provides detailed observations of turbulence scaling laws and energy transfer in a CME, highlighting the role of shock-wind interactions in turbulence development.

Findings

Third-order moment scaling law observed in CME regions

Increased energy transfer rate in the CME sheath

Turbulence persists and develops during the CME evolution

Abstract

Turbulence properties are examined before, during and after a coronal mass ejection (CME) detected by the6Wind spacecraft on July 2012. The power-law scaling of the structure functions, providing information on the7power spectral density and flatness of the velocity, magnetic filed and density fluctuations, were examined. The8third-order moment scaling law for incompressible, isotropic magnetohydrodynamic turbulence was observed9in the preceding and trailing solar wind, as well as in the CME sheath and magnetic cloud. This suggests that10the turbulence could develop sufficiently after the shock, or that turbulence in the sheath and cloud regions11was robustly preserved even during the mixing with the solar wind plasma. The turbulent energy transfer rate12was thus evaluated in each of the regions. The CME sheath shows an increase of energy transfer rate, as13expected from the lower level of Alfv\'enic fluctuations and suggesting the role of the shock-wind interaction as14an additional source of energy for the turbulent cascade.