Collisional Transport of Solar Wind Plasma during its Journey from the Sun to the Earth

Parker Solar Probe (PSP) is the first spacecraft to dive deep into the solar corona, making the first-ever direct measurements of the plasma within the corona and offering unprecedented observations of solar wind plasma in its nascent form. In their journey outward from the Sun, the streams that make up solar wind plasmas interact, expand, and evolve in a number of different ways. Previous theoretical work has shown that coulomb collisions are one of the many factors that dictate the thermodynamic properties that distinguish different kinds of solar wind. Plasma instruments onboard the PSP spacecraft, making up the Solar Wind Electrons, Alphas, and Protons (SWEAP) suite, provide an opportunity to further test and investigate this well-known collisional hypothesis by identifying solar wind plasma streams that are also measured by other spacecraft such as Solar Orbiter and Wind during suitable conjunctions. These multi-point observations will be compared to collisional predictions to evaluate the evolution of plasma distributions as they travel through the inner heliosphere. This work examines the degree to which collisional transport can explain the radial evolution of plasma parameters within 1 au.