Imaging the Earth's magnetosphere response to solar wind variability

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It is known that soft X-rays are produced in the Earth's magnetosheath and cusps by the process of charge exchange between solar wind ions and neutrals in the Earth's exosphere. The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE - https://mssl.ucl.ac.uk/SMILE/) is a joint mission of the European Space Agency and the Chinese Academy of Sciences that will study the interaction of the solar wind with the Earth's magnetosphere. At the end of 2024 the mission will take into space four instruments, two of them being imagers, the Soft X-ray Imager (SXI) and the UV Imager (UVI). SXI will take X-ray images of the dayside magnetosphere with the purpose of studying its response to solar wind variations in a totally new way.In order to understand the data SMILE will return, we are simulating the X-rays emitted by the cusp and magnetosheath and the output of SXI.The motivation behind this PhD project is that of studying large-scale magnetic reconnection at the dayside magnetopause and transitions between different magnetospheric modes. Dayside reconnection is induced by an increase in the solar wind dynamic pressure and/or a southward interplanetary magnetic field (IMF) turning. So far, many modelling and observational studies have been devoted to the magnetospheric response to solar wind pressure jumps (e.g. interplanetary shocks) and to solar wind tangential/rotational discontinuities. These phenomena are part of what we call 'space weather', representing the impact of solar wind variability on environmental conditions in near Earth space, which can have severe disrupting consequences on our technological infrastructure, in space and on the ground. A particularly interesting issue is the magnetospheric response to southward IMF turnings. This is important in magnetospheric physics because the IMF component orthogonal to the equatorial plane is thought to be one of the most important driving parameters for the solar wind - magnetosphere interaction. And it is a topic that has great potential for investigations applying SMILE imaging.Questions that the project will try to find an answer to are like: Which types of solar wind structures are related to southward IMF turnings? Are they the sort of conditions that lead to geomagnetic storms and substorms? In addition, there are many other unresolved issues that a PhD project in this area can address. For example, we know that the magnetopause shape and position are different for northward and southward IMF but the empirical and MHD models we have do not describe them accurately. MHD model runs, combined with observations from spacecraft, could better constrain the mathematical form of the magnetopause shape.