Multi-point observations and eigenmode instability analysis of tearing-induced reconnection in the heliospheric current sheet related to primary solar wind

The Heliospheric Current Sheet (HCS) is the largest structure imposed by the solar magnetic field on the heliosphere. HCSs are usually embedded in dense plasma — Heliospheric Plasma Sheets (HPS) — generated from coronal streamers. Previous observations around 1 AU show that the solar wind is slow and dense around HCS. Recent near-sun HCS observations, however, reveal that these structures are highly dynamic, with velocity jets frequently created by magnetic reconnections. To understand the morphology of reconnections and the radial evolution of HCS, we analyze HCS crossing events with PSP, Solar Orbiter, and L1-based spacecraft during their alignments. We also study the triggering mechanisms of HCS reconnections through linear stability analysis of MHD equations describing magnetic and velocity shear. We find that the eigenfunctions of tearing modes agree with the multiple polarity reversals and intermittent velocity jets observed in the near-sun HCSs, strongly supporting that the reconnections are triggered by tearing instabilities.