Tearing instability and periodic density perturbations in the slow solar wind

In sharp contrast with the fast solar wind, which is thought to be coming from coronal holes, the origin of the slow wind is still intensely debated. Intermittent by nature and enriched with low FIP elements -akin what is observed in closed coronal loops- the slow wind is thought by many to be born in bursty events at the open/close boundary of coronal streamers. The slow wind also shows large density perturbations, which have been shown to be periodic. These density perturbations could be associated with flux ropes ejected from the tip of helmet streamers, as shown recently by the WISPR white light imager onboard Parker Solar Probe. Helmet streamers are indeed likely unstable and very dynamic. In this work, we study the possibility that the main process controlling the periodic release of flux ropes from streamers is a tearing mode. We use MHD simulations of the solar wind and corona to reproduce realistic configurations and outflows surrounding the heliospheric current sheet. The reconnection process, and in particular the fastest growing tearing mode is characterized at low Lundquist number and we use linear theory to extrapolate to the so-called ideal regime, and compare with observations. If confirmed, this process could then explain both the origin of the periodic density perturbations and the composition of (part of?) the slow solar wind.