Large scale 6300A, 5577A, 3914A dayside auroral morphology

Simultaneous observations at 6300A, 5577A, and 3914A by the ISIS-2 satellite are used to examine the morphology of auroras in the noon sector. While a miniumum in intensity is generally observed in the 5577A and 3914A emissions from approximately 10 to 12 MLT, the 6300A emissions may be most intense there. The latitudinal extent of 6300A emissions is much greater than that of 5577A and 3914A and discrete features are generally not apparent in the 6300A emission. Peak levels of 6300A emission may occur at noon, prenoon, or afternoon and thus 6300A emission is not confined to the ''gap'' or minimum in the dayside discrete aurora seen at 5577A and 3914A. Substantial 6300A emission occurs on closed field lines which is evidently due to boundary layer plasma. No optical signature of direct entry particles is identified