Abstract Closed magnetic fields play an important role in plasma transport and atmospheric escape from the Martian dayside ionosphere. Leveraging in‐situ magnetic field data from the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, we conduct a statistical analysis of closed magnetic field behavior under varying upstream conditions. Our findings indicate that closed magnetic fields on Mars’ dayside tend to align with the draping direction of the Interplanetary Magnetic Field, resulting in (a) a downward JXB force in the dayside ionosphere and (b) reduced shear angles between the draped and closed field lines. This behavior of the closed fields arises from the ionospheric induced magnetic field and may (a) inhibit upward plasma transport in the upper ionosphere and (b) modify the locations and likelihood of magnetic reconnections on Mars’ dayside, ultimately impacting Mars’ atmospheric escape rate.

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