Details
Zusammenfassung: <jats:p>In this case study we report a substorm, 23 March 2007, which exhibited oscillations with a period of ∼135 s in three substorm phenomena all of which were one‐to‐one correlated. The in‐situ observations are from one THEMIS spacecraft (8.3 <jats:italic>R</jats:italic><jats:sub><jats:italic>E</jats:italic></jats:sub> geocentric distance) and the geosynchronous LANL‐97A spacecraft. The focus here is on the intensification phase during which THEMIS was conjugate to the region of auroral brightening and its foot point was near the high‐latitude ground station Kiana. The following results will be demonstrated: (1) THEMIS and LANL‐97A (time‐delayed) recorded periodic ion injections (&gt;100 keV). (2) Near‐conjugate high‐latitude ground magnetometer data show very large Pi2 (<jats:italic>δH</jats:italic>∼150 nT) with a 6‐s time delay compared to the THEMIS ion injections. (3) Low‐latitude ground magnetometer data also show Pi2 with the same waveform as the high‐latitude Pi2 but with longer time delays (20–31 s). (4) Auroral luminosity was periodically modulated during the intensification phase. (5) All three signatures (ion injections, ground Pi2, optical modulation) had the same periodicity of ∼135 s but with various time delays with respect to the THEMIS ion injections. These observations demonstrate that the three substorm phenomena had a common source which controlled the periodicity.</jats:p>
ISSN: 1944-8007
0094-8276
DOI: 10.1029/2008gl033969