Global environmental constraints on magnetic reconnection at the magnetopause from in situ measurements

The location of magnetic reconnection at the Earth's magnetopause is a longstanding question in the field of magnetospheric physics. Various models  (Alexeev et al. 1998, Borovsky 2013, Trattner et al. 2007, etc) predicting the position of the X-line have been proposed. These models often rely on quantities whose global spatial distributions at the magnetopause are typically obtained through numerical simulations. In this study, we attempt to reconstruct these global distributions using only in-situ measurements. To do this, we have used statistical learning to automatically select in-situ data from four missions (Cluster, Doublestar, THEMIS, MMS). The 3D reconstruction of the magnetic field draping in the dayside magnetosheath (Michotte de Welle et al. 2022) reveals significant differences with the model of Kobel et Fluckiger 1994 for a certain range of IMF orientations. As this magnetostatic model is frequently used to predict magnetic shear at the magnetopause, we will examine the implications of these differences on the X-lines maximizing this quantity (Trattner et al. 2007). We will also extend this discussion to other relevant quantities such as current density and the Cassak-Shay reconnection rate, which can also be accessed using in-situ measurements.