Accession Number : AD0274486

Title :   STRUCTURE AND ATTENUATION OF HYDROMAGNETIC EMISSIONS, VOLUME I

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : TEPLEY,LEE R.

Report Date : 06 APR 1962

Pagination or Media Count : 1

Abstract : Experimentally observed properties of hydromagnetic emissions, which are geomagnetic fluctuations in the frequency range 0.5 to 5 cps, are discussed. Results are presented of a frequencytime analysis of selected events which occurred during both magnetically quiet and disturbed periods. The observation that most hm emissions are characterized by a fine structure consisting of a superposition of short wave trains of rapidly increasing frequency is of particular interest. Also presented are the results of a statistical analysis relating the following quantities as observed simultaneously: (1) Times of occurrence of the emissions, (2) Conditions in the ionosphere overhead, and (3) Geomagnetic activity. It is concluded that the characteristics of the signals are consistent with their generation above the ionosphere and their subsequent transmission downward by hydromagnetic waves. Results are also included of geomagnetic fluctuations observed in the frequency range 5 to 25 cps. Bands of enhanced activity, associated with the earth-ionosphere cavity resonances, are found at frequencies near 7, 14, and 20 cps. (Author)

Descriptors :   *GEOMAGNETISM, IONOSPHERE, MAGNETOMETERS, PROPAGATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE