Parker Solar Probe observations of proton beams simultaneous with ion-scale waves

Abstract

Parker Solar Probe (PSP), NASA's latest and closest mission to the Sun, is on a journey to investigate fundamental enigmas of the inner heliosphere. This paper reports initial observations made by the Solar Probe Analyzer for Ions (SPAN-I), one of the instruments in the Solar Wind Electrons Alphas and Protons (SWEAP) instrument suite. We address the presence of secondary proton beams in concert with ion-scale waves observed by FIELDS, the electromagnetic fields instrument suite. We show two events from PSP's 2nd orbit that demonstrate signatures consistent with wave-particle interactions. We showcase 3D velocity distribution functions (VDFs) measured by SPAN-I during times of strong wave power at ion-scales. From an initial instability analysis, we infer that the VDFs departed far enough away from local thermodynamic equilibrium (LTE) to provide sufficient free energy to locally generate waves. These events exemplify the types of instabilities that may be present and, as such, may guide future data analysis characterizing and distinguishing between different wave-particle interactions.

arXiv comment24 pages, 9 figures, 2 tables

References in corpus (22)

• Magnetic fluctuation power near proton temperature anisotropy instability thresholds in the solar wind
• The multi-scale nature of the solar wind
• Perpendicular Ion Heating by Low-Frequency Alfven-Wave Turbulence in the Solar Wind
• Switchbacks in the near-Sun magnetic field: long memory and impact on the turbulence cascade
• The Solar Probe Cup on Parker Solar Probe
• The Solar Probe ANalyzers -- Electrons on Parker Solar Probe
• Ion Scale Electromagnetic Waves in the Inner Heliosphere
• Magnetic field kinks and folds in the solar wind
• Proton Temperature Anisotropy Variations in Inner Heliosphere Estimated with First Parker Solar Probe Observations
• Predicted Impacts of Proton Temperature Anisotropy on Solar Wind Turbulence
• A comparison of Alpha Particle and Proton Beam Differential flow in Collisionally Young Solar Wind
• Cross Helicity Reversals In Magnetic Switchbacks
• Instabilities Driven by the Drift and Temperature Anisotropy of Alpha Particles in the Solar Wind
• Stochastic Heating, Differential Flow, and the Alpha-to-Proton Temperature Ratio in the Solar Wind
• A nonlinear theory of the parallel firehose and gyrothermal instabilities in a weakly collisional plasma
• A Majority of Solar Wind Intervals Support Ion-Driven Instabilities
• The Dispersion Relations and Instability Thresholds of Oblique Plasma Modes in the Presence of an Ion Beam
• A Parallel-Propagating Alfvénic Ion-Beam Instability in the High-Beta Solar Wind
• Parallel-propagating Fluctuations at Proton-kinetic Scales in the Solar Wind are Dominated by Kinetic Instabilities
• NHDS: The New Hampshire Dispersion Relation Solver
• Wavelet transforms and their applications to MHD and plasma turbulence: a review
• Linear Stability in the Inner Heliosphere: Helios Reëvaluated

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• Switchbacks: statistical properties and deviations from alfvénicity
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• Inferred Linear Stability of Parker Solar Probe Observations using One- and Two-Component Proton Distributions
• Inner-Heliosphere Signatures of Ion-Scale Dissipation and Nonlinear Interaction
• Strong perpendicular velocity-space in proton beams observed by Parker Solar Probe
• Statistical analysis of orientation, shape, and size of solar wind switchbacks
• The Electromagnetic Signature of Outward Propagating Ion-Scale Waves
• Proton Core Behaviour Inside Magnetic Field Switchbacks
• The Radial Distribution of Ion-scale Waves in the Inner Heliosphere
• On quasi-parallel whistler waves in the solar wind
• Modeling ion beams, kinetic instabilities, and waves observed by the Parker Solar Probe near perihelia
• The Structure and Origin of Switchbacks: Parker Solar Probe Observations
• Wave-particle energy transfer directly observed in an ion cyclotron wave
• Ion-Driven Instabilities in the Inner Heliosphere I: Statistical Trends
• Magnetic reconnection as a mechanism to produce multiple protonpopulations and beams locally in the solar wind
• Estimation of turbulent proton and electron heating rates via Landau damping constrained by Parker Solar Probe observations
• Parker Solar Probe Observations of High Plasma Beta Solar Wind from Streamer Belt
• Electromagnetic Proton Beam Instabilities in the Inner Heliosphere: Energy Transfer Rate, Radial Distribution, and Effective Excitation
• Cross Helicity and the Helium Abundance as an in situ Metric of Solar Wind Acceleration
• Fully Kinetic Simulations of Proton-Beam-Driven Instabilities from Parker Solar Probe Observations
• The Temperature, Electron, and Pressure Characteristics of Switchbacks: Parker Solar Probe Observations
• Magnetic reconnection-driven energization of protons up to 400 keV at the near-Sun heliospheric current sheet
• Modeling hot, anisotropic ion beams in the solar wind motivated by the Parker Solar Probe observations near perihelia
• Growth of Outward Propagating Fast-Magnetosonic/Whistler Waves in the Inner Heliosphere Observed by Parker Solar Probe
• The Evolution of Heavy Ion Abundances with Solar Activity
• Decoding the formation of hammerhead ion populations observed by Parker Solar Probe
• A Tale of Two Shocks
• Characterizing the Impact of Alfvén Wave Forcing in Interplanetary Space on the Distribution of near-Earth Solar Wind Speeds
• Evolution of an Alfvén Wave-Driven Proton Beam in the Expanding Solar Wind
• On the Regulation of the Solar Wind Helium Abundance by the Hydrogen Compressibility
• Scope and limitations of ad hoc neural network reconstructions of solar wind parameters
• Hybrid simulations of the proton beam instabilities in the young solar wind. The formation of hammerhead-like distributions