X-ray detection of jets in the terrestrial magnetosheath: Implications for SMILE mission

In this paper we present a numerical study on the soft X-ray detection of high-speed plasma jets that are moving within the terrestrial magnetosheath. For this purpose, we developed a simulation approach able to provide X-ray images from a virtual soft X-ray telescope launched inside the simulation domain. Our methodology is based on global MHD simulations of the magnetosphere coupled with a kinematic approach on the propagation of jets. The soft X-ray emission is calculated using a fluid-like quantification of the solar wind charge exchange process. We considered different parameters for the high-speed plasma jets and tested various setups for the virtual soft X-ray telescope. The numerical solutions show that, under certain circumstances, the soft X-ray signature of high-speed plasma jets is visible in the magnetosheath. We discuss here the implications of our results for the upcoming Solar wind-Magnetosphere-Ionosphere Link Explorer (SMILE) mission. SMILE is a joint mission of the European Space Agency and Chinese Academy of Science that shall be launched in spring 2026 to observe in soft X-rays the interaction between the solar wind plasma and the terrestrial magnetosphere. Also, we discuss the potential implications of our simulations for future soft X-ray telescopes.