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A STUDY OF X-RAYS AT HIGH ALTITUDES IN THE AURORAL ZONE AND RELATED GEOPHYSICAL PHENOMENA

Thesis/Dissertation ·
OSTI ID:4162862
A series of instrumented balloon flights was carried out at College, Alaska in which correlations of auroral-zone x-ray bursts with auroral'' ionospheric radio-wave absorption events and geomagnetic field variations were studied. X-rays were detected by Geiger counters approximately 10% of the time. There was a pronounced tendency for the events to occur in the late night and early morning hours except during times of magnetic storms, when they occurred throughout the day. The average electron-energy flux at the top of the atmosphere during the period of these flights was estimated to be roughly 10/sup 11/ ev/cm/sup 2/ sec. Ionospheric radio-wave absorption, as measured by the College riometer, and the x-ray events showed an obvious, and in some cases detailed, correspondence. The relationship between the x-ray events and geomagnetic disturbance was of a more general nature. X rays were observed at the times of positive and negative geomagnetic bays and quite extensively during geomagnetic storms. Sometimes the bursts were closely related to magnetic field changes, and at other times they were not. The x-ray counting rate at balloon altitudes was calculated for various electronenergy distributions using a simplified model of the Compton scattering process. Consideration was given to the quantitative relationship between radio-wave absorption and the x-ray flux. The results indicate that direct ionization by the same energetic electrons which produce the observed x rays is responsible for most of the ionospheric radio wave absorption which accompandies these events, and that in most cases, the electrons bring in enough energy to produce a visible aurora and could be the cause of certain auroral forms. (M.P.G.)
Research Organization:
Originating Research Org. not identified
NSA Number:
NSA-18-000949
OSTI ID:
4162862
Country of Publication:
Country unknown/Code not available
Language:
English