Chemistry and dynamics of SF₆ injections into the F region

The chemistry of SF 6 vapor reacting in the F region is critically examined. The SF 6 molecule dissociatively attaches an electron, producing the SF 5 − ion. Reaction between an ambient O + ion and the SF 5 − yields mutual neutralization. During the neutralizaton process, an electronically excited oxygen atom, O(¹ D ), may be produced which will subsequently emit a 630.0‐nm photon. A release of 20 kg of SF 6 into an ambient O + ion concentration of 10 5 cm −3 at 300‐km altitude is considered. The 630.0‐nm airglow intensity may increase following the release. The negative ion plasma is shown to be marginally unstable to a gradient drift instability.