Solar Wind Effects on Ion Temperature and Density in Mercury's Central Plasma Sheet

Mercury has a complicated, reconnection-dominated magnetosphere; understanding the areas where plasma is found will give insight to how this complex system works. We focus on Mercury's central plasma sheet (CPS), one of three main areas where plasma is found in the magnetosphere. Using data from the Fast Imaging Plasma Spectrometer (FIPS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft we analyze measurements of the solar wind and planetary ions over orbital observations from March 2011 to April 2015. With MESSENGER's extensive observations of Mercury's plasma composition around the planet's space environment, we determine how the temperature and density of the ions in the CPS are connected to dynamics in Mercury's magnetotail and how they are affected by the solar wind. We find that proton density decreases linearly with solar wind speed while proton temperature increases linearly with solar wind speed, which is consistent with previous results (Gershman et al., 2014). The post-midnight side is hotter than the pre-midnight side, with average temperatures of 22.7MK and 20.04MK, respectively. This is also consistent with previous results (Sun et al., 2017). Proton density increases as the thickness of the plasma sheet increases, and decreases as you move further downtail. Proton temperature is greater closer to the planet.