Relation between magnetopause position and dayside reconnection rate under quasi-steady solar wind dynamic pressure

The Lunar Environment Heliospheric X-ray Imager (LEXI) and Solar wind-Magnetosphere-Ionosphere Link Explorer (SMILE) will observe the magnetopause motion in soft X-rays to understand dayside reconnection modes as a function of solar wind conditions after their respective launches in 2024 and 2025. To support their successful science closure, we investigate the relationship between the magnetopause position and the dayside reconnection rate by utilizing Super Dual Auroral Radar Network (SuperDARN) observations and the empirical magnetopause models of Shue et al. 1998 and Lin et al. 2010 and Tsyganenko magnetic field models. We select events when the IMF rotates during quasi-steady solar wind dynamic pressure. We first estimate the dayside reconnection rate by calculating the electric field along the open-closed magnetic field boundary (OCB) in the OCB moving reference frame. Then, we estimate the magnetopause location near the local noon by inputting NASA OMNI solar wind data into the empirical magnetopause models and tracing the last closed field lines from the empirical magnetic field models. The results shows that the reconnection rate is anti-correlated with magnetopause position. It generally increases as the magnetopause moves inward and vice versa. The magnetopause moves earthward up to 1 Re during continuous reconnection. Our result also confirms that the reconnection rate increases as the empirical coupling efficiency between solar wind and the magnetosphere increases.