Enhanced proton parallel temperature inside patches of switchbacks in the inner heliosphere

Abstract

Switchbacks are discrete angular deflections in the solar wind magnetic field that have been observed throughout the heliosphere. Recent observations by Parker Solar Probe (PSP) have revealed the presence of patches of switchbacks on the scale of hours to days, separated by 'quieter' radial fields. We aim to further diagnose the origin of these patches using measurements of proton temperature anisotropy that can illuminate possible links to formation processes in the solar corona. We fitted 3D bi-Maxwellian functions to the core of proton velocity distributions measured by the SPAN-Ai instrument onboard PSP to obtain the proton parallel, $T_{p,\Vert }$, and perpendicular, $T_{p,\perp }$, temperature. We show that the presence of patches is highlighted by a transverse deflection in the flow and magnetic field away from the radial direction. These deflections are correlated with enhancements in $T_{p,\Vert }$, while $T_{p,\perp }$ remains relatively constant. Patches sometimes exhibit small proton and electron density enhancements. We interpret that patches are not simply a group of switchbacks, but rather switchbacks are embedded within a larger-scale structure identified by enhanced $T_{p,\Vert }$ that is distinct from the surrounding solar wind. We suggest that these observations are consistent with formation by reconnection-associated mechanisms in the corona.

Letter accepted as part of the PSP Special Issue in A&A

References in corpus (31)

• The Solar Orbiter mission -- Science overview
• Solar Coronal Jets: Observations, Theory, and Modeling
• Switchbacks in the near-Sun magnetic field: long memory and impact on the turbulence cascade
• The Solar Probe Cup on Parker Solar Probe
• First in-situ Measurements of Electron Density and Temperature from Quasi-Thermal Noise Spectroscopy with Parker Solar Probe/FIELDS
• In-situ switchback formation in the expanding solar wind
• Parker Solar Probe observations of proton beams simultaneous with ion-scale waves
• Magnetic field kinks and folds in the solar wind
• Proton Temperature Anisotropy Variations in Inner Heliosphere Estimated with First Parker Solar Probe Observations
• Ion kinetic energy conservation and magnetic field strength constancy in multi-fluid solar wind Alfvénic turbulence
• Pearle's Hidden-Variable Model Revisited
• On slow solar wind with high Alfvénicity: from composition and microphysics to spectral properties
• Scattering of Strahl Electrons in the Solar Wind between 0.3 and 1 au: Helios Observations
• Coronal-Jet-Producing Minifilament Eruptions as a Possible Source of Parker Solar Probe (PSP) Switchbacks
• Cross Helicity Reversals In Magnetic Switchbacks
• Radial evolution of the solar wind in pure high-speed streams: HELIOS revised observations
• Diagnosing solar wind origins using in-situ measurements in the inner heliosphere
• Coronal Electron Temperature inferred from the Strahl Electrons in the Inner Heliosphere: Parker Solar Probe and Helios observations
• Localized magnetic field structures and their boundaries in the near-Sun solar wind from Parker Solar Probe measurements
• Statistical analysis of orientation, shape, and size of solar wind switchbacks
• The origin of slow Alfvénic solar wind at solar minimum
• Apparent temperature anisotropies due to wave activity in the solar wind
• A new inner heliosphere proton parameter data set from the Helios mission
• Properties of solar polar coronal plumes constrained by Ultraviolet Coronagraph Spectrometer data
• Alpha particle thermodynamics in the inner heliosphere fast solar wind
• The Evolution of Inverted Magnetic Fields Through the Inner Heliosphere
• Proton Core Behaviour Inside Magnetic Field Switchbacks
• Simulated Encounters of Parker Solar Probe with A Coronal-Hole Jet
• Modeling the Early Evolution of a Slow Coronal Mass Ejection Imaged by the Parker Solar Probe
• Visualizing Rotations and Composition of Rotations with Rodrigues' Vector
• Revisiting the frequency drift rates of decameter type III solar bursts observed in July-August 2002

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• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
• A solar source of Alfvénic magnetic field switchbacks: {\em in situ} remnants of magnetic funnels on supergranulation scales
• Evolution of switchbacks in the inner Heliosphere
• Evolution of large-amplitude Alfvén waves and generation of switchbacks in the expanding solar wind
• Statistical analysis of orientation, shape, and size of solar wind switchbacks
• The Near-Sun Streamer Belt Solar Wind: Turbulence and Solar Wind Acceleration
• Direct evidence for magnetic reconnection at the boundaries of magnetic switchbacks with Parker Solar Probe
• Patches of magnetic switchbacks and their origins
• Exploring the Solar Wind from its Source on the Corona into the Inner Heliosphere during the First Solar Orbiter - Parker Solar Probe Quadrature
• Flux rope merging and the structure of switchbacks in the solar wind
• The Structure and Origin of Switchbacks: Parker Solar Probe Observations
• The preferential orientation of magnetic switchbacks, implications for solar magnetic flux transport
• Total Electron Temperature Derived from Quasi-Thermal Noise Spectroscopy In the Pristine Solar Wind: Parker Solar Probe Observations
• Density And Velocity Fluctuations of Alpha Particles in Magnetic Switchbacks
• Conditions for proton temperature anisotropy to drive instabilities in the solar wind
• Evidence for the helicity barrier from measurements of the turbulence transition range in the solar wind
• Large Amplitude Switchback Turbulence: Possible Magnetic Velocity Alignment Structures
• Analytic Model and Magnetohydrodynamic Simulations of Three-dimensional Magnetic Switchbacks
• The Temperature, Electron, and Pressure Characteristics of Switchbacks: Parker Solar Probe Observations
• Switchback Deflections Beyond the Early Parker Solar Probe Encounters
• Modeling hot, anisotropic ion beams in the solar wind motivated by the Parker Solar Probe observations near perihelia
• Cross-scale energy transfer from fluid-scale Alfvén waves to kinetic-scale ion acoustic waves in the Earth's magnetopause boundary layer
• Ambipolar electric field and potential in the solar wind estimated from electron velocity distribution functions
• Radial evolution of thermal and suprathermal electron populations in the slow solar wind from 0.13 to 0.5 au : Parker Solar Probe Observations
• Relation of Microstreams in the Polar Solar Wind to Switchbacks and Coronal X-ray Jets