Evolution of The Proton Velocity Distribution due to Stochastic Heating in the Near-Sun Solar Wind

Abstract

We investigate how the proton distribution function evolves when the protons undergo stochastic heating by strong, low-frequency, Alfvén-wave turbulence under the assumption that $\beta$ is small. We apply our analysis to protons undergoing stochastic heating in the supersonic fast solar wind and obtain proton distributions at heliocentric distances ranging from 4 to 30 solar radii. We find that the proton distribution develops non-Gaussian structure with a flat core and steep tail. For $r>5R_{\mathrm{S}}$, the proton distribution is well approximated by a modified Moyal distribution. Comparisons with future measurements from \emph{Solar Probe Plus} could be used to test whether stochastic heating is occurring in the solar-wind acceleration region.

arXiv comment6 pages, 6 figures, accepted for publication in The Astrophysical Journal

References in corpus (12)

• Self-consistent Coronal Heating and Solar Wind Acceleration from Anisotropic Magnetohydrodynamic Turbulence
• Spectrum of magnetohydrodynamic turbulence
• Alfven Wave Solar Model (AWSoM): Coronal Heating
• Perpendicular Ion Heating by Low-Frequency Alfven-Wave Turbulence in the Solar Wind
• Dependence of solar wind power spectra on the direction of the local mean magnetic field
• Incorporating Kinetic Physics into a Two-Fluid Solar-Wind Model with Temperature Anisotropy and Low-Frequency Alfven-Wave Turbulence
• Alfven Wave Reflection and Turbulent Heating in the Solar Wind from 1 Solar Radius to 1 AU: an Analytical Treatment
• Spectral scaling laws in MHD turbulence simulations and in the solar wind
• Alfven Wave Turbulence and Perpendicular Ion Temperatures in Coronal Holes
• Stochastic Heating, Differential Flow, and the Alpha-to-Proton Temperature Ratio in the Solar Wind
• Observational Test of Stochastic Heating in Low-$\beta$ Fast Solar Wind Streams
• Perpendicular Ion Heating by Reduced Magnetohydrodynamic Turbulence

Cited by in corpus (18)

• The multi-scale nature of the solar wind
• Hybrid-Kinetic Simulations of Ion Heating in Alfvénic Turbulence
• Diagnosing collisionless energy transfer using field-particle correlations: gyrokinetic turbulence
• Inferred Linear Stability of Parker Solar Probe Observations using One- and Two-Component Proton Distributions
• A Prospectus on Kinetic Heliophysics
• Nature of stochastic ion heating in the solar wind: testing the dependence on plasma beta and turbulence amplitude
• On stochastic heating and its phase-space signatures in low-$\beta$ kinetic turbulence
• Diagnosing collisionless energy transfer using field-particle correlations: Alfven-Ion Cyclotron Turbulence
• The Enhancement of Proton Stochastic Heating in the near-Sun Solar Wind
• On the temperature of the solar wind
• Stochastic proton heating by kinetic-Alfvén-wave turbulence in moderately high-$\beta$ plasmas
• A Quasi-Linear Diffusion Model for Resonant Wave-Particle Instability in Homogeneous Plasma
• Whistler Waves As a Signature of Converging Magnetic Holes in Space Plasmas
• Electron-ion heating partition in imbalanced solar-wind turbulence
• Quasilinear Consequences of Turbulent Ion Heating by Magnetic Moment Breaking
• A Unified Phenomenology of Ion Heating in Low-$\beta$ Plasmas: Test-Particle Simulations
• Dropouts of Fully Stripped Ions in the Solar Wind: A Diagnostic for Wave Heating versus Reconnection
• Thresholdless stochastic particle heating by a single wave