Multi‐Instrument Observations of the Effects of a Solar Wind Pressure Pulse on the High Latitude Ionosphere: A Detailed Case Study of a Geomagnetic Sudden Impulse

The effects of a solar wind pressure pulse on the terrestrial magnetosphere have been observed in detail across multiple datasets. The communication of these effects into the magnetosphere is known as a positive geomagnetic sudden impulse (+SI), and are observed across latitudes and different phenomena to characterize the propagation of +SI effects through the magnetosphere. A superposition of Alfvén and compressional propagation modes are observed in magnetometer signatures, with the dominance of these signatures varying with latitude. For the first time, collocated lobe reconnection convection vortices and region 0 field aligned currents are observed preceding the +SI onset, and an enhancement of these signatures is observed as a result of +SI effects. Finally, cusp auroral emission is observed collocated with the convection and current signatures. For the first time, simultaneous observations across multiple phenomena are presented to confirm models of +SI propagation presented previously. Key Points A positive sudden impulse (SI) is observed on 16 June 2012 at 20:19 UT in SYM‐H A superposition of Alfvén and compressional propagation modes are observed in magnetometer data Collocated lobe reconnection vortices and region 0 field aligned currents are enhanced by the SI