Using Electron Measurements from MAVEN to study the Magnetosheath of Mars

Abstract:

There are several examples of collisionless shocks in our solar system, each creating a unique space environment around a planetary body. Studying these different collisionless shocks is crucial in understanding how energy and momentum are transferred from the solar wind to the planetary space environment. Mars provides a particularly interesting environment since it has no global intrinsic magnetosphere but instead an induced magnetosphere as well as strong localized crustal fields. Measurements of electron spectra from the Solar Wind Electron Analyzer (SWEA) aboard the Mars Atmospheric and Volatile Environment (MAVEN) spacecraft will be utilized to study the martian magnetosheath. However, charged particle instruments like SWEA have issues in measuring the low energy electron population due to internally produced secondary electrons. The issue becomes especially prominent when encountering a hot electron population (such as that in the Martian magnetosheath), giving overestimates of electron density and underestimates of electron temperature. First, an iterative approach to removing these secondary electrons is introduced, which can potentially be applied to other charged particle instruments on other missions. Once the secondary electrons have been separated from the ambient electrons, important plasma properties, such as the electron density and temperature, can be extracted. Global maps of these properties in the Martian space environment will be presented to understand how the electron population evolves as it moves through the sheath. Temperature anisotropy measurements will also be utilized to find out when the electron population is capable of driving instabilities.