Ground-based optical observations of artificial auroras generated with a rocket-borne electron accelerator

Davis, T. Neil; Hallinan, T. J.; Trichel, M. C.; Hess, W. N.

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Abstract

Ground-based image orthicon television systems detected 5 artificial auroras produced by electron beams directed downward from a rocket-borne accelerator flown January 26, 1969 from Wallops Island. One observed artificial aurora was produced with an electron beam of energy 4.9 kev, current 490 ma and duration 0.1 sec. The other 4 were from electron beams of energy 8.7 kev, current 490 ma and duration 1.0 sec. From the observed duration of these 4 auroras (1.4 sec) and other data it is concluded that the ratio of N2+ 1st Neg to 0I 5577 emission was 3 to 7. Widths of artificial auroral rays (130 + 50 m) and altitudes of lower edges (104 km for 8.7 kev beams) are in agreement with calculations by Berger, Seltzer and Maeda assuming Coulomb scattering. The observations show no delay in the arrival of the electron beam and indicate that a major fraction or all of the energy entered the atmosphere in a well-confined beam.

Description

UAG R-210

Abstract – Acknowledgments – List of tables – List of figures – I. Introduction – II. Expected positions of artificial auroras – III. Location of ground-based observing instruments – IV. Optical instrumentation - A. Visual observers – B. Direct photography cameras – 1. Super Schmidt cameras – 2. BC-4 ballistic camera – 3. All-sky camera – C. Photoelectric imaging devices – 1. Image orthicon television systems – 2. Image intensifiers – D. Photometric instrumentation – E. Timing and synchronization of optical systems – V. Ground-based radio frequency observations – A. VLF observations – B. Radar observations – VI. Observational procedures during the experiment – VII. Brief survey of initial results – VIII. Instrumental limitations of the image orthicon - A. Image orthicon sensitivity and value for intensity measurements – 1. Dynamic range – 2. Maximum sensitivity - B. Limiting resolution and error in width measurement – 1. Aperture distortion – 2. Amplifier frequency response – 3. Effect of time integration on scaling bias – 4. Blooming and beam bending – 5. Secondary electron effects – C. Temporal response of the image orthicon system – IX. Results of image orthicon observations – A. General appearance and position of artificial auroras – B. Intensities of artificial auroras – C. Widths of the artificial auroral rays – D. Timing, duration and temporal variation of the artificial auroras – 1. Accuracy of timing measurements – 2. Onset times and durations of the artificial auroras – X. Summary and discussion of results – XI. Interpretations of results and conclusions - A. Estimate of energy deposition – B. Implication of extended ray duration – References.

Date

1970-04

Publisher

Geophysical Institute at the University of Alaska Fairbanks

Type

Report

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GI Reports