Authors: Ramiz Qudsi (Boston University), Brian Walsh (Boston University), Jeff Broll(Los Alamos National Lab), Emil Atz(Boston University), Stein Haaland(The University Center in Svalbard)

Reconnection at Earth’s magnetopause drives magnetospheric convection and provides mass and
energy input into the magnetosphere/ionosphere system thereby driving the coupling between solar
wind and terrestrial magnetosphere. Despite its importance, the factors governing the location
of dayside magnetopause reconnection are not well understood. Though a few models can predict
X-line locations reasonably well, the underlying physics is still unresolved. In this study we
present results from a comparative analysis of 274 magnetic reconnection events as observed by
the Magnetospheric Multiscale (MMS) mission to determine what quantities affect the accuracy of
such models and are most strongly associated with the occurrence of dayside magnetopause
reconnection. We also attempt to determine under what upstream solar wind conditions each global
X-line models becomes least reliable.