We examine Polar data for several high‐altitude cusp crossings to characterize “Cusp Diamagnetic Cavities” (CDCs). In particular, we determine the relationship between the magnetic field and thermal pressure of the local plasma. The cusp is characterized by high density and the presence of stagnant solar wind plasma throughout. The CDCs represent a distinct region within the cusp, possessing a depressed and turbulent magnetic field in addition to the other cusp properties. We find the CDCs are colocated with “Cusp Energetic Particle” (CEP) events. In CDCs, depressions in the field are strongly correlated to local enhancements in plasma density and thus pressure, supporting the “diamagnetic” label. No correlation between field and plasma is found in the cusp outside of the CDC. The colocation of CDCs and CEP events suggests constraints on the origin of CEPs.
