The beam-heated electrons provide at most a few eV of energy, and their effect is considered to be only on the very low-lying energy states. The two 1 1 lowest-lying metastable states of 0^, a Lg and b Ag, yield infrared bands at 1.27 p and 0.86 p, respectively, and would show abnormal intensity in the region below 100 km. The forbidden 0 6300,6364A doublet would, as noted, show abnormal brightness in the F region, where deactivation collisions are infrequent. The 4.3-p and 6.5-P emission enhancement for CO^ and H^O at low altitudes has been mentioned previously. Only at highly pronounced runaway heating below 100 km would higher energy states of available constituents be appreciably excited by the beam; the next highest metastable atomic oxygen state, for example, requires about 4 eV and yields the bright o green auroral and airglow line at 5577A. While normally the electron and neutral temperatures at low (below 100 km) altitudes are essentially equal, RF heating would raise the Te several times greater than Tn and thereby lead to the various excitations. Another complex result would come from the fact that a small fraction of the electron heat is not radiated away but is transferred to heating the neutral components; the enhanced reaction rates of the processes of atmospheric chemistry for the many constituents of the D region will not be analyzed here. The effect at heights below 100 km, seen locally for the infrared emissions by CO^, H^O, and 0?, might roughly double the naturally occurring intensities. The normal daytime intensity of 6300A, peaking around 250 km and coming to a total of about 4 kilorayleighs, comes mostly from photoelectrons, photodissociation, and dissociative recombination with only about 1% from thermal electron impact. The RF heating would bring the latter contribution up to several kilorayleighs itself. At night especially, this heating would be the dominant source of the light, and the glow could be faintly visible as well as highly measurable. It would be as bright as a good stable auroral red arc (SAR arc) at midlatitudes, and equivalent to a weak auroral display. While it is conceivable that special studies of processes might take advantage of the uniquely localized parameters within the beam, the masking effect of the artificial excitation would vitiate most studies of the natural
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