Switchbacks in the near-Sun magnetic field: long-range correlations and impact on the turbulence cascade
Résumé
One of the most striking observations made by Parker Solar Probe during its first solar encounter is the omnipresence of rapid polarity reversals in a magnetic field that is otherwise mostly radial. These so-called switchbacks, which are associated with radial jets of plasma, strongly affect the dynamics of the magnetic field. We concentrate here on their macroscopic properties. First, we find that these structures are self-similar, and have neither a characteristic magnitude, not a characteristic duration. The waiting time statistics shows clear evidence for long-range correlations, with indications that they are connected deep inside the corona. Interestingly, the spectral scaling of inertial range turbulence differ when the switchback structures are included or not in the analysis. These results suggest that Kolmogorov-like scaling in the magnetic field fluctuations of the solar wind spectrum is driven by the dynamics of the switchbacks, and is not intrinsic to the fluctuations in the inner heliosphere.