Modeling ion beams, kinetic instabilities, and waves observed by the Parker Solar Probe near perihelia

Abstract

Recent in-situ observations from the Parker Solar Probe (PSP) mission in the inner heliosphere near perihelia show evidence of ion beams, temperature anisotropies, and kinetic wave activity, which are likely associated with kinetic heating and acceleration processes of the solar wind. In particular, the proton beams were detected by PSP/SPAN-I and related magnetic fluctuation spectra associated with ion-scale waves were observed by the FIELDS instrument. We present the ion velocity distribution functions (VDFs) from SPAN-I and the results of 2.5D and 3D hybrid-particle-in-cell (hybrid-PIC) models of proton and alpha particle super-Alfvenic beams that drive ion kinetic instabilities and waves in the inner-heliospheric solar wind. We model the evolution of the ion VDFs with beams, ion relative drifts speeds, and ion temperature anisotropies for solar wind conditions near PSP perihelia. We calculate the partition of energies between the particles (ions) along and perpendicular to the magnetic field, as well as the evolution of magnetic energy and compare to observationally deduced values. We conclude that the ion beam driven kinetic instabilities in the solar wind plasma near perihelia are important components in the cascade of energy from fluid to kinetic scale, an important component in the solar wind plasma heating process.

Accepted for publication in The Astrophysical Journal

References in corpus (10)

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• Strong Preferential Ion Heating is Limited to within the Solar Alfven Surface
• The Electromagnetic Signature of Outward Propagating Ion-Scale Waves
• Relative drifts and temperature anisotropies of protons and $\alpha$ particles in the expanding solar wind -- 2.5D hybrid simulations
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Cited by in corpus (6)

• The Radial Distribution of Ion-scale Waves in the Inner Heliosphere
• Fully Kinetic Simulations of Proton-Beam-Driven Instabilities from Parker Solar Probe Observations
• Modeling hot, anisotropic ion beams in the solar wind motivated by the Parker Solar Probe observations near perihelia
• Decoding the formation of hammerhead ion populations observed by Parker Solar Probe
• Evolution of an Alfvén Wave-Driven Proton Beam in the Expanding Solar Wind
• Hybrid simulations of the proton beam instabilities in the young solar wind. The formation of hammerhead-like distributions