The ionospheric response to the cme event of 6–11January 1997

Abstract

An active aurora was observed at Eureka, Canada (88.9° N magnetic) following the arrivalat the magnetopause of the shock front resulting from the solar Coronal Mass Ejection of 6January 1997. This onset at 02:20 UT on 10 January marked the beginning of an aurora whichcontinued until at least 15:00 UT on 11 January, as viewed from both Eureka and the CANOPUSsite at Ft Smith (67.8° N magnetic). There were enhanced OI 630 nm polar F-region emissionsthroughout this period, with the IMF B z controlling their form. When B z was positive, there were continuous polar arcs; when B z turned negative there were F-layer patches on open field lines. While the strong H β observed over Ft Smith (240 R) in addition to the extended 630 nm emissions and theirpersistence over two days suggested a red aurora of global proportions, it apparently did notextend to latitudes below 60°. There was a moderate magnetic storm associated with the aurora,but the D st index reached only −81 nT on 10 January.