New Evidence on the Origin of Solar Wind Microstreams/Switchbacks

Abstract

Microstreams are fluctuations in the solar wind speed and density associated with polarity-reversing folds in the magnetic field (also denoted switchbacks). Despite their long heritage, the origin of these microstreams/switchbacks remains poorly understood. For the first time, we investigated periodicities in microstreams during Parker Solar Probe (PSP) Encounter 10 to understand their origin. Our analysis was focused on the inbound corotation interval on 2021 November 19-21, while the spacecraft dove toward a small area within a coronal hole (CH). Solar Dynamics Observatory remote-sensing observations provide rich context for understanding the PSP in-situ data. Extreme ultraviolet images from the Atmospheric Imaging Assembly reveal numerous recurrent jets occurring within the region that was magnetically connected to PSP during intervals that contained microstreams. The periods derived from the fluctuating radial velocities in the microstreams (approximately 3, 5, 10, and 20 minutes) are consistent with the periods measured in the emission intensity of the jetlets at the base of the CH plumes, as well as in larger coronal jets and in the plume fine structures. Helioseismic and Magnetic Imager magnetograms reveal the presence of myriad embedded bipoles, which are known sources of reconnection-driven jets on all scales. Simultaneous enhancements in the PSP proton flux and ionic (${}^3$He, ${}^4$He, Fe, O) composition during the microstreams further support the connection with jetlets and jets. In keeping with prior observational and numerical studies of impulsive coronal activity, we conclude that quasiperiodic jets generated by interchange/breakout reconnection at CH bright points and plume bases are the most likely sources of the microstreams/switchbacks observed in the solar wind.

arXiv commentApJ Letters, 19 pages, 12 figures

References in corpus (27)

• Solar Orbiter: Exploring the Sun-heliosphere connection
• The Magnetic Topology of Solar Eruptions
• In-situ switchback formation in the expanding solar wind
• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
• A Breakout Model for Solar Coronal Jets with Filaments
• Magnetic Reconnection as the Driver of the Solar Wind
• 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
• A solar source of Alfvénic magnetic field switchbacks: {\em in situ} remnants of magnetic funnels on supergranulation scales
• Interchange reconnection as the source of the fast solar wind within coronal holes
• Solar Energetic Particles (Second Edition)
• Observation of High-speed Outflow on Plume-like Structures of the Quiet Sun and Coronal Holes with SDO/AIA
• 3D Radio and X-Ray Modeling and Data Analysis Software: Revealing Flare Complexity
• Coronal-Jet-Producing Minifilament Eruptions as a Possible Source of Parker Solar Probe (PSP) Switchbacks
• Evidence for polar jets as precursors of polar plume formation
• STEREO Observations of Quasi-Periodically Driven High Velocity Outflows in Polar Plumes
• Observational Signatures of Simulated Reconnection Events in the Solar Chromosphere and Transition Region
• Characteristic scales of magnetic switchback patches near the Sun and their possible association with solar supergranulation and granulation
• Evidence For The Magnetic Breakout Model in an Equatorial Coronal-Hole Jet
• On the Size of Structures in the Solar Corona
• Multiwavelength Study of Equatorial Coronal-Hole Jets
• First Detection of Plasmoids from Breakout Reconnection on the Sun
• Quasiperiodic Energy Release and Jets at the Base of Solar Coronal Plumes
• Small-scale Flux Emergence, Coronal Hole Heating, and Flux-tube Expansion: A Hybrid Solar Wind Model
• From Pseudostreamer Jets to CMEs: Observations of the Breakout Continuum
• Plumelets: Dynamic Filamentary Structures in Solar Coronal Plumes
• Noise-gating to clean astrophysical image data

Cited by in corpus (8)

• Solar Spicules, Filigrees and Solar Wind Switchbacks
• Propagation of untwisting solar jets from the low-beta corona into the super-Alfvénic wind: Testing a solar origin scenario for switchbacks
• Tracing magnetic switchbacks to their source: An assessment of solar coronal jets as switchback precursors
• Thin coronal jets and plasmoid-mediated reconnection: Insights from Solar Orbiter observations and Bifrost simulations
• Synthetic Remote-sensing and In-situ Observations of Fine-scale Structure in a Pseudostreamer Coronal Mass Ejection through the Solar Corona
• Dominance of 2-Minute Oscillations near the Alfvén Surface
• SynCOM: An Empirical Model for High-Resolution Simulations of Transient Solar Wind Flows
• High-resolution observations of small-scale activity in coronal hole plumes