Determining Shock 3D-Structure Using ARTEMIS High-Resolution Solar Wind Observations

Abstract:

After migrating to lunar orbit in 2010, two of the five THEMIS spacecraft, renamed ARTEMIS, encounter the solar wind ~70% of each lunar month. From separations of ~12-28 thousand km the two spacecraft measure electric and magnetic fields from DC up to 8 kHz, and electrons and ions between3 eV and 1 MeV at spin resolution (4s). Their close separation and the rapid temporal sampling of the field and plasma, allow us to analyze interplanetary shock structures at the shock front and compare shock signatures at the two locations to understand the magnetic field and electron behavior inside the shock thickness and the shock spatial and temporal stationarity. Using burst data triggered on shock crossings we can resolve the kinetic structure of the shock including the magnetic field rotation and electron motion therein. When the connection line of the two probes is roughly perpendicular to the shock normal, the shock spatial variation can be determined; when the connection line is near the shock normal, the shock temporal stationarity can be explored. Our analysis reveals the shock’s 3D-structure and stationarity on kinetic scales for comparison with theoretical models.