Disentangling the Anomalous Acceleration of Coronal Mass Ejections via Turbulent Energy Conversion

Predicting the interplanetary kinematics of coronal mass ejections (CMEs) heavily relies on aerodynamic drag models. However, these frameworks inherently neglect the complex internal magnetic and turbulent forces of the ejecta, occasionally failing to capture anomalous kinematic behaviors. A striking example is the 2021 November CME, observed during a remarkably tight radial alignment between Solar Orbiter and Wind (at 0.85 and 0.98 au, respectively), which exhibited a counterintuitive bulk acceleration despite propagating through a slower ambient solar wind. This letter disentangles the observed kinematic puzzle by tracing the physical origin of the anomalous acceleration to the multiscale turbulent evolution of the ejecta. A wavelet-based analysis of the ideal magnetohydrodynamic invariants and the turbulent energy budget reveals a severe topological degradation of the embedded flux rope, evidenced by a substantial drop in magnetic helicity. The application of the exact Politano–Pouquet law demonstrates an anomalously fast depletion of the turbulent energy transfer rate. Crucially, empirical thermodynamic estimates prove that this massive depletion of turbulent energy does not contribute to local plasma heating, as the ejecta undergoes significant cooling. This internal energy is instead demonstrated to be converted into macroscopic mechanical work. The continuous magnetic erosion weakens the flux rope’s restraining magnetic tension, while the cascading energy heavily enhances the internal turbulent pressure. This disrupted equilibrium generates a net outward macroscopic Lorentz force, acting as the physical internal “motor” that overcomes the aerodynamic drag. These findings highlight the paramount importance of coupling macroscopic kinematics with microscale turbulent processes in space weather forecasting.