Signatures of in situ generated ion-scale coherent structures in the solar wind by magnetic reconnection
Abstract
The origin of ion-scale coherent structures in the solar wind is a matter of considerable debate, in particular whether they are passively advected from a distant source or are locally generated by non-linear processes. Here we investigate the possibility that disruption of Alfvenic turbulence by the onset of the tearing mode instability may lead to the formation of ion-scale coherent structures. We use a wavelet technique to identify ion-scale coherent structures with large amplitude magnetic fluctuations and study how their occurrence correlates with changes in the ion-scale spectral index and beta_e. We find that ion-scale coherent structures occur most frequently when 0.2 < beta_e < 0.8 and the break scale is only slightly larger than the ion sound radius, which agrees with the parameters where magnetic reconnection may control the ion-scale spectral break of the turbulent spectrum. For these intervals the statistical properties of ion-scale turbulence are consistent with the presence of vortex-like structures. We suggest that the onset of collisionless magnetic reconnection significantly affects the nature of plasma turbulence around the ion gyroscale by generating small-scale magnetic structures.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2019)
- Pub Date:
- May 2019
- Bibcode:
- 2019shin.confE..96V