Ion Scale Electromagnetic Waves in the Inner Heliosphere

Abstract

Understanding the physical processes in the solar wind and corona which actively contribute to heating, acceleration, and dissipation is a primary objective of NASA's Parker Solar Probe (PSP) mission. Observations of coherent electromagnetic waves at ion scales suggests that linear cyclotron resonance and non-linear processes are dynamically relevant in the inner heliosphere. A wavelet-based statistical study of coherent waves in the first perihelion encounter of PSP demonstrates the presence of transverse electromagnetic waves at ion resonant scales which are observed in 30-50\% of radial field intervals. Average wave amplitudes of approximately 4 nT are measured, while the mean duration of wave events is of order 20 seconds; however long duration wave events can exist without interruption on hour-long timescales. Though ion scale waves are preferentially observed during intervals with a radial mean magnetic field, we show that measurement constraints, associated with single spacecraft sampling of quasi-parallel waves superposed with anisotropic turbulence, render the measured quasi-parallel ion-wave spectrum unobservable when the mean magnetic field is oblique to the solar wind flow; these results imply that the occurrence of coherent ion-scale waves is not limited to a radial field configuration. The lack of strong radial scaling of characteristic wave amplitudes and duration suggests that the waves are generated {\em{in-situ}} through plasma instabilities. Additionally, observations of proton distribution functions indicate that temperature anisotropy may drive the observed ion-scale waves.

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Cited by in corpus (40)

• The Evolution and Role of Solar Wind Turbulence in the Inner Heliosphere
• Switchbacks in the near-Sun magnetic field: long memory and impact on the turbulence cascade
• 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
• Parker Solar Probe observations of proton beams simultaneous with ion-scale waves
• Violation of the zeroth law of turbulence in space plasmas
• The In Situ Signature of Cyclotron Resonant Heating
• Inferred Linear Stability of Parker Solar Probe Observations using One- and Two-Component Proton Distributions
• Anisotropy of Solar-Wind Turbulence in the Inner Heliosphere at Kinetic Scales: PSP Observations
• Sunward propagating whistler waves collocated with localized magnetic field holes in the solar wind: Parker Solar Probe observations at 35.7 Sun radii
• Inner-Heliosphere Signatures of Ion-Scale Dissipation and Nonlinear Interaction
• A Merged Search-Coil and Fluxgate Magnetometer Data Product for Parker Solar Probe FIELDS
• Strong perpendicular velocity-space in proton beams observed by Parker Solar Probe
• Kinetic Scale Slow Solar Wind Turbulence in the Inner Heliosphere: Co-existence of Kinetic Alfvén Waves and Alfvén Ion Cyclotron Waves
• The Enhancement of Proton Stochastic Heating in the near-Sun Solar Wind
• The Radial Dependence of Proton-scale Magnetic Spectral Break in Slow Solar Wind during PSP Encounter 2
• Turbulence in the outer heliosphere
• Coherent events at ion scales in the inner Heliosphere: \textit{Parker Solar Probe} observations during the first Encounter
• The Electromagnetic Signature of Outward Propagating Ion-Scale Waves
• The Ion Transition Range of Solar Wind Turbulence in the Inner Heliosphere: Parker Solar Probe Observations
• Kinetic-scale current sheets in near-Sun solar wind: properties, scale-dependent features and reconnection onset
• The radial variation of the solar wind turbulence spectra near the kinetic break scale from Parker Solar Probe measurements
• General dispersion properties of magnetized plasmas with drifting bi-Kappa distributions. DIS-K: DIspersion Solver for Kappa plasmas
• The Radial Distribution of Ion-scale Waves in the Inner Heliosphere
• On quasi-parallel whistler waves in the solar wind
• Wave-particle energy transfer directly observed in an ion cyclotron wave
• Estimation of turbulent proton and electron heating rates via Landau damping constrained by Parker Solar Probe observations
• Observational evidence for solar wind proton heating by ion-scale turbulence
• Magnetic helicity signature and its role in regulating magnetic energy spectra and proton temperatures in the solar wind
• Electromagnetic Proton Beam Instabilities in the Inner Heliosphere: Energy Transfer Rate, Radial Distribution, and Effective Excitation
• Evidence for the helicity barrier from measurements of the turbulence transition range in the solar wind
• Fully Kinetic Simulations of Proton-Beam-Driven Instabilities from Parker Solar Probe Observations
• Coherence of ion cyclotron resonance for damping ion cyclotron waves in space plasmas
• 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
• Decoding the formation of hammerhead ion populations observed by Parker Solar Probe
• The effects of finite electron inertia on helicity-barrier-mediated turbulence
• Energetic Ion Composition as a Means of Investigating the Physical Origins of Alpha Particle Heavy Magnetic Switchbacks
• Turbulent heating in collisionless low-beta plasmas: imbalance, Landau damping, and electron-ion energy partition
• Evidence of a "current-mediated" turbulent regime in space and astrophysical plasmas