A complicated evolution of a newly created Polar Cap Ionization Patch

Polar cap patches is a common phenomenon in the Earth polar ionosphere. They are associated with turbulent instabilities giving rise to severe disturbances to High Frequency (HF) radio communications, over-the-horizon radar location errors, and disruption and errors to satellite navigation and communication systems. Their formation and evolution are still poorly understood, particularly under disturbed space weather conditions, and there is not yet established any forecasting tool to predict their occurrence. Here we report the first direct and continuous monitoring of a complicated evolution of a newly created patch during a geomagnetic storm. The observations reveal that the patch was segmented from the high density "tongue" of ionization (TOI) by a subauroral polarization stream (SAPS) near the polar cap boundary associated with a substorm . The patch did not follow the expected route across the polar cap from dayside to nightside, but instead was halted by a local disturbance in the polar cap due to a rapidly changing in interplanetary magnetic field (IMF) condition and evolved in a particular way with quickly fading associated with the high-latitude lobe reconnection. These results give essential new insight into the formation of the patches and their evolution as controlled by the IMF, and offer a key opportunity for improving polar ionospheric modeling and Global Navigation Satellite System (GNSS) scintillation and space weather forecasts.