Magnetic and auroral substorms associated with storm sudden commencements and sudden impulses

In order to study the diurnal occurrences of the ssc triggered magnetic substorm at the high latitude station, Syowa, 134 ssc\u27s were selected in the period from 1966 to 1979. The statistical results show that the substorms are easily excited by ssc\u27s in the late evening and midnight hours. Especially, from 00h to 03h geomagnetic local time, 80% of the ssc\u27s examined are associated with excitations of substorms. By using the all-sky photographs taken every 10s and the space-time auroral diagrams for the electron (OI 5577A) and proton (H_β, 4861A) auroras, the behavior of auroras associated with ssc\u27s at Syowa Station are investigated. The ssc auroral substorms in the midnight sector show similar characteristics to those of the substorms excited by the physical processes inherent in the magnetosphere not associated with ssc\u27s. In the evening sector, both electron and proton auroras suddenly brighten when an ssc takes place, and show expansion towards the equator. From the auroral aspect during the phase preceding the ssc triggered substorm, it is found that the auroras with luminosity of a few kR in λ 4278A are covering the region in which the ssc auroral substorm starts