Parker Solar Probe: Advancing Our Understanding of Plasmas in the Young Solar Wind*

Parker Solar Probe (PSP), having just completed its 9th perihelion encounter with the Sun on August 9th, 2021, has been providing unprecedented in situ measurements of the plasma and associated electromagnetic fields from as close as 16 solar radius (11.1 Gm) from the Sun's surface. In doing so, the mission aims to answer long standing questions about the structure and dynamics of the magnetic fields and trace the flow of energy through this near-Sun environment, as well as determine what mechanisms accelerate and transport energetic particles in this region. In this talk, we will review results from recent encounters that have provided new insights into the behavior of diverse processes which play a role in the plasma thermodynamics in this region including wave-particle interactions, magnetic reconnection, and the evolution of turbulent fluctuations, as well as the behavior of larger scale structures such as coronal mass ejections, stream interaction regions, and the heliospheric current sheet. We will focus in particular on how the more recent encounters with smaller perihelion distances from the Sun, enabled by recurrent gravity assists at Venus, have shed light on radial variations in the plasma properties of the Sun's extended atmosphere and changes in the solar wind as we approach the Alfven surface.