Identifying Kinetic Phase Space Signatures of Turbulent Dissipation

Understanding the nature and importance of various proposed heating processes that result from turbulent dissipation is imperative in describing a range of collisionless systems. We highlight the importance of kinetic phase space signatures of heating as pivitol in providing necessary contraints on turbulent dissipation. Understanding mechanisms through diffusive approximation schemes is largely a tractable problem that can be studied with modern plasma instrumentation. We highlight recent progress in understanding signatures of kinetic dissipation and particle heating using the Parker Solar Probe (PSP) mission. Importantly, our observations reveal that a range of heating mechanisms (stochastic heating, cyclotron resonance, and Landau damping) are likely important in explaining observed phase-space plasma signatures. The use of non-parametric approximations to particle distribution functions (via Hermite polynomials and Radial Basis Functions) is pivotal in understanding and characterizing these heating mechanisms. While our observations are from PSP, we discuss furture implementation of these techniques on current and future plasma missions (MMS and Plasma Observatory).