Investigating magnetic field structure at moon distance: A single pass example

Since 2011, ARTEMIS spacecraft 1 and 2 take observations in the solar wind and magnetotail as they orbit around the Moon at +/-60 Re. With the state-of-the-art magnetic field and plasma instruments, they perform the first systematic, two-point observations of the mid-to-distant tail and give an opportunity for the scientist to study the detailed structure of the mid-to-distant tail at -60 Re as well as the tail dynamics since the era of ISEE-3 and Wind in 1970s and mid-1990s. In this study, we use magnetic field observations to perform vector mappings of the magnetotail structure in xy-, xz, and yz-planes. We present our preliminary results based on the investigation of four trajectory passes. The one of the example pass we present here corresponds to the IMF orientation in-y direction. Even it is a single pass, we can see the IMF By effect on the orientation of the magnetic field vectors within the magnetotail. Mapping along the trajectory also shows several unexpected tail magnetic field orientations within the central magnetotail which we attribute to the fact that it is a single pass and thus it may reflect the singular, local short term variations occurred in the central tail as the spacecraft moves. We run MHD model, SWMF-BATSRUS, at CCMC for this single pass to see how much temporally the model and observations agree. The results will be discussed in the frame of understanding the magnetotail behavior in response to the IMF By on a temporal scale.