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We analyse the signature and origin of transient structures embedded in theslow solar wind, and observed by the Wide-Field Imager for Parker Solar Probe(WISPR) during its first ten passages close to the Sun. WISPR provides a newin-depth vision on these structures, which have long been speculated to be aremnant of the pinch-off magnetic reconnection occurring at the tip of helmetstreamers. We pursued the previous modelling works of Reville (2020b, 2022)that simulate the dynamic release of quasi-periodic density structures into theslow wind through a tearing-induced magnetic reconnection at the tip of helmetstreamers. Synthetic WISPR white-light (WL) images are produced using a newlydeveloped advanced forward modelling algorithm that includes an adaptive gridrefinement to resolve the smallest transient structures in the simulations. Weanalysed the aspect and properties of the simulated WL signatures in severalcase studies that are typical of solar minimum and near-maximum configurations.Quasi-periodic density structures associated with small-scale magnetic fluxropes are formed by tearing-induced magnetic reconnection at the heliosphericcurrent sheet and within 3-7Rs. Their appearance in WL images is greatlyaffected by the shape of the streamer belt and the presence ofpseudo-streamers. The simulations show periodicities on ~90-180min, ~7-10hr and~25-50hr timescales, which are compatible with WISPR and past observations.This work shows strong evidence for a tearing-induced magnetic reconnectioncontributing to the long-observed high variability of the slow solar wind.

Variability of the slow solar wind: New insights from modelling and PSP-WISPR observations