Studies of Equatorial 630.0 nm Airglow Enhancements Produced by a Chemical Release in the F-Region

摘要

A sky-mapping filter photometer has been used to determine the 630.0 nm airglow enhancement produced by explosive release of 3 x 10 to the 26th power carbon dioxide molecules into the F-region at 320 km altitude on 8 September 1982 as part of project BIME. The enhancement is produced when carbon dioxide molecules engage in atom transfer with the F-region oxygen ions to form molecular oxygen(+) ions, which subsequently dissociatively recombine with the ambient electrons to produce O(1D) atoms to yield the 630.0 nm radiation. The morphology of the enhanced airglow region has been traced in a series of 630.0 nm intensity contour maps as a function of time, the enhancement reaching a central brightness of approximately 400 R about 2 min after release and a diameter of about 250 km some 3 min after release. The measurements of central intensity and enhanced region radius as a function of time are compared with model calculations by Mendillo and Herniter of diffusive expansion of carbon dioxide molecules from either a point release or form an initial, extended volume. While peak intensities are reasonably reproduced, the measured decay of the 630.0 nm intensity and the growth in size of the enhanced region are rather different from the model predictions. The measured 200 m/s drift southeastward of the enhanced region is consistent with the motion of the neutral thermosphere determined from optical doppler shifts less than an hour earlier.