From measurements of two rocket flights and from laboratory investigations auroral EUV emissions are identified. Contrary to the airglow, emissions from ionized nitrogen are present in the auroral emission spectra below 80 nm.
Photometric images of 130.4-, 337.1-, 391.4-, and 557.7-nm auroral airglow emissions are presented for November 16, 1980, and December 9, 1981. Unique observations and new data reduction techniques allow 360' imaging of the local auroral emissions on both days and a view of spatial and temporal variability. The 1980 aurorae, one nonpulsating and one pulsating, are located in the morning sector. We find that the 1980 diffuse, nonpulsating aurora was located < 75 km from the rocket in a northern location with respect to the rocket and was produced by electrons With a characteristic energy of 200-300 eV. The pulsating aurora was located > 75 km in a western location and was produced by electrons with a characteristic energy of 2-3 keV. Both the near (northern) and far (western) aurorae had motion and size characteristics consistent with northeasterly drift rates of 200-500 m s 'l and 30-50 km in size, respectively. The 1981 flight observed a stable are in the evening sector. The arc was produced by electrons with a characteristic energy of 1-3 keV and had a probable l/e width of approximately 75 km. For both flights, the 557.7/391.4 and 337.1/391.4 ratios were approximately constant. INTRODUCTION The flight of the E-2 payload during the Energy Budget Campaign (EBC) in 1980, which included the EF-11 spectometer/photometer, and the reflight of the spectrometer/photometer experiment a year later in 1981 provided derailed information on the spatial, temporal, and spectral characteristics of diffuse and stable arc aurorae, respectively. The EBC, as summarized by Offermann [1985], studied the structure and variability of the upper atmosphere due to indirect solar energy inputs. Seidl et al. [1983] and Schmidtke et al. [1985] describe the two rocket flights and the EF-11 instrument in detail. Briefly, the EF-11 instrument package consisted of spectrometer and photometer units. Nine detectors scanned wavelength ranges in two spectrometers from 50-to 240nm with 1-nm resolution and from 105-to 640-nm with 3nm resolution. Nine additional photometer channels observed discrete emissions from the extreme ultraviolet (EUV) to the visible pan of the electromagnetic spectrum. The photometer fields of view for channels 6 through 9 (130.4-, 337.1-, 391.4-, and 557.7-nm, respectively) used in this study were 4'.6 horizontal and 4'.7 vertical (i.e., along the rocket axis) or approximately 9øx10 ø. The photometer (halfwidth) passband of channel 6 (130.4-nm) was 17.5-nm with < 1% transmission at 121.6-nm, of channel 7 (337.1nm) was 9.0-nm, of channel 8 (391.4-nm) was 7.8-nm, and of channel 9 (557.7-nm) was 3.7-nm. In both flights, the rockets were stabilized nearly vertically and the instruments sensed horizontally, with the spectrometer and photometer units viewing 180' apart. This instrument configuration, combined with the -2.5 Hz spin frequency of each rocket, allowed a 360' view as a function of altitude in the auroral region above the launch facilities at Kiruna, Sweden (67.9 N, 21.1 E) for both flights. The first flight was on Nove...
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