Ion‐Scale Wave Emission and Absorption for Non‐Maxwellian Velocity Distributions in the Inner Heliosphere

Abstract Hot and tenuous plasmas have velocity distribution functions (VDFs) significantly different from Maxwellian distributions. Characterizing how these differences impact wave damping and emission necessitates sophisticated methods for determining the associated dielectric plasma response. The Arbitrary Linear Plasma Solver ( ALPS ) is a tool for calculating such responses through numerical integration of arbitrary gyrotropic VDFs, rather than using analytical models, for example bi‐Maxwellians, for the VDF. We consider dispersion relations for beam‐driven instabilities, proton‐cyclotron waves, and kinetic Alfven waves, derived using example VDFs from Parker Solar Probe/SPANi measurements during Encounters 22 and 23. The same kinds of waves are supported, but non‐Maxwellian structures drive significant changes in the amount of energy absorbed by the charged particles or released into the waves, altering expected heating rates from these waves in the inner heliosphere.