Observations of Energetic-Particle Population Enhancements along Intermittent Structures near the Sun from Parker Solar Probe

Abstract

Observations at 1 au have confirmed that enhancements in measured energetic particle fluxes are statistically associated with "rough" magnetic fields, i.e., fields having atypically large spatial derivatives or increments, as measured by the Partial Variance of Increments (PVI) method. One way to interpret this observation is as an association of the energetic particles with trapping or channeling within magnetic flux tubes, possibly near their boundaries. However, it remains unclear whether this association is a transport or local effect; i.e., the particles might have been energized at a distant location, perhaps by shocks or reconnection, or they might experience local energization or re-acceleration. The Parker Solar Probe (PSP), even in its first two orbits, offers a unique opportunity to study this statistical correlation closer to the corona. As a first step, we analyze the separate correlation properties of the energetic particles measured by the \isois instruments during the first solar encounter. The distribution of time intervals between a specific type of event, i.e., the waiting time, can indicate the nature of the underlying process. We find that the \isois observations show a power-law distribution of waiting times, indicating a correlated (non-Poisson) distribution. Analysis of low-energy \isois data suggests that the results are consistent with the 1 au studies, although we find hints of some unexpected behavior. A more complete understanding of these statistical distributions will provide valuable insights into the origin and propagation of solar energetic particles, a picture that should become clear with future PSP orbits.

Accepted for publication in The Astrophysical Journal Supplement, PSP special issue

References in corpus (4)

• Magnetic Reconnection and Intermittent Turbulence in the Solar Wind
• Magnetic Discontinuities in Magnetohydrodynamic Turbulence and in the Solar Wind
• Clustering of Intermittent Magnetic and Flow Structures near Parker Solar Probe's First Perihelion -- A Partial-Variance-of-Increments Analysis
• The clustering of polarity reversals of the geomagnetic field

Cited by in corpus (13)

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• Clustering of Intermittent Magnetic and Flow Structures near Parker Solar Probe's First Perihelion -- A Partial-Variance-of-Increments Analysis
• Geometry of Magnetic Fluctuations near the Sun from PSP
• Observations of heating along intermittent structures in the inner heliosphere from PSP data
• Magnetic field intermittency in the solar wind: PSP and SolO observations ranging from the Alfven region out to 1 AU
• Statistical analysis of intermittency and its association with proton heating in the near Sun environment
• Preferential Proton over Electron heating from coherent structures during the first perihelion of Parker Solar Probe
• Taylor microscale and effective Reynolds number near the Sun from PSP
• Energy transfer, discontinuities and heating in the inner solar wind measured with a weak and local formulation of the Politano-Pouquet law
• Transfer of Entropy between the Magnetic Field and Solar Energetic Particles during an Interplanetary Coronal Mass Ejection
• Magnetic Switchback Occurrence Rates in the Inner Heliosphere: Parker Solar Probe and 1 au