Direct evidence for magnetic reconnection at the boundaries of magnetic switchbacks with Parker Solar Probe

Abstract

Parker Solar Probe's first encounters with the Sun revealed the presence of ubiquitous localised magnetic deflections in the inner heliosphere; these structures, often called switchbacks, are particularly striking in solar wind streams originating from coronal holes. We report the direct evidence for magnetic reconnection occuring at the boundaries of three switchbacks crossed by Parker Solar Probe (PSP) at a distance of 45 to 48 solar radii of the Sun during its first encounter. We analyse the magnetic field and plasma parameters from the FIELDS and SWEAP instruments. The three structures analysed all show typical signatures of magnetic reconnection. The ion velocity and magnetic field are first correlated and then anti-correlated at the inbound and outbound edges of the bifurcated current sheets with a central ion flow jet. Most of the reconnection events have a strong guide field and moderate magnetic shear but one current sheet shows indications of quasi anti-parallel reconnection in conjunction with a magnetic field magnitude decrease by $90\%$. Given the wealth of intense current sheets observed by PSP, reconnection at switchbacks boundaries appears to be rare. However, as the switchback boundaries accomodate currents one can conjecture that the geometry of these boundaries offers favourable conditions for magnetic reconnection to occur. Such a mechanism would thus contribute in reconfiguring the magnetic field of the switchbacks, affecting the dynamics of the solar wind and eventually contributing to the blending of the structures with the regular wind as they propagate away from the Sun.

11 pages, 7 figures, 2 tables, accepted for publication in A&A, PSP special issue (v2: typos correction)

References in corpus (20)

• Switchbacks in the near-Sun magnetic field: long memory and impact on the turbulence cascade
• The Solar Probe Cup on Parker Solar Probe
• Why does steady-state magnetic reconnection have a maximum local rate of order 0.1?
• The Solar Probe ANalyzers -- Electrons on Parker Solar Probe
• In-situ switchback formation in the expanding solar wind
• Magnetic connectivity of the ecliptic plane within 0.5 AU : PFSS modeling of the first PSP encounter
• Switchbacks as signatures of magnetic flux ropes generated by interchange reconnection in the corona
• Shear-Driven Transition to Isotropically Turbulent Solar Wind Outside the Alfven Critical Zone
• Magnetic field kinks and folds in the solar wind
• Parker Solar Probe In-Situ Observations of Magnetic Reconnection Exhausts During Encounter 1
• Cross Helicity Reversals In Magnetic Switchbacks
• Coronal-Jet-Producing Minifilament Eruptions as a Possible Source of Parker Solar Probe (PSP) Switchbacks
• Switchbacks: statistical properties and deviations from alfvénicity
• Enhanced proton parallel temperature inside patches of switchbacks in the inner heliosphere
• Sunward propagating whistler waves collocated with localized magnetic field holes in the solar wind: Parker Solar Probe observations at 35.7 Sun radii
• Localized magnetic field structures and their boundaries in the near-Sun solar wind from Parker Solar Probe measurements
• Predicting the Structure of the Solar Corona and Inner Heliosphere during Parker Solar Probe's First Perihelion Pass
• Predicting the Solar Wind at Parker Solar Probe Using an Empirically Driven MHD Model
• MMS Observations of Whistler and Lower Hybrid Drift Waves Associated with Magnetic Reconnection in the Turbulent Magnetosheath
• Parker Solar Probe Observations of Suprathermal Electron Flux Enhancements Originating from Coronal Hole Boundaries

Cited by in corpus (16)

• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
• Observation of Magnetic Switchback in the Solar Corona
• Patches of magnetic switchbacks and their origins
• Small-scale Magnetic Flux Ropes with Field-aligned Flows via the PSP In-situ Observations
• Flux rope merging and the structure of switchbacks in the solar wind
• Suprathermal Ion Energy spectra and Anisotropies near the Heliospheric Current Sheet crossing observed by the Parker Solar Probe during Encounter 7
• Solar wind current sheets and deHoffmann-Teller analysis: First results of DC electric field measurements by Solar Orbiter
• Magnetic reconnection as a mechanism to produce multiple protonpopulations and beams locally in the solar wind
• Whistler waves generated inside magnetic dips in the young solar wind: observations of the Search-Coil Magnetometer on board Parker Solar Probe
• Density And Velocity Fluctuations of Alpha Particles in Magnetic Switchbacks
• Are Switchback boundaries observed by Parker Solar Probe closed?
• Evidence of oblique electron acoustic solitary waves triggered by magnetic reconnection in Earth's magnetosphere
• Analytic Model and Magnetohydrodynamic Simulations of Three-dimensional Magnetic Switchbacks
• Magnetic reconnection as an erosion mechanism for magnetic switchbacks
• Switchbacks near Boundaries of Small-scale Magnetic Flux Ropes in the Young Solar Wind from Parker Solar Probe Observations
• The impact of Alfvenic shear flow on magnetic reconnection and turbulence