A STUDY OF HYDROMAGNETIC EMISSIONS. Scientific Report No. 2

Technical Report · Fri Apr 14 04:00:00 EST 1961

OSTI ID:4809288

Tepley, L R

Considerable geomagnetic micropulsation data were collected in the interval from February to December 1060. In the discussion, however, attention is focused on the collection, reduction, analysis, and interpretation of a single useful data sample obtained during a 4-day period, November 18 to 21. To facilitate the interpretation of these data, consideration was given to observations in the same frequeney range by other workers, and in particular to the observations of H. Benioff at the California Institute of Technology. These observatlons are dlseussed, aad Benloff's experimental results are compared with the theoretical calculations just completed at Lockheed bv W. E. Francis. The agreement between experiment and theory is consistent with the hypothesns that the signals of nnterest are generatcd above the ionosphere and are propagated downward through ihe ionosphere by hydromagnetic waves. The instrumentation for data collection and reduction is described. The general appearance of the signal on a . frequency-time plot (sonogram) is discussed, and the term hydromagnetic (hm) emission is defined with reference to the appearance of the signal on a frequency-time display. Of particular interest is the long duration (up to 5 hours) of some hm emissions, and the simultaneous occurrence of many emissions in groups of the same slope (time rate of change of frequency). The signals recorded at the Lockheed Magnetic Observatory are compared with signals recorded simultaneously at a number of stations of the Caltech network. Consideration is given to the relationship between the occurrence of the signals and other geophysical effects observed during the unusua1 period of solar and geomagnetic activlty. A positive correlation is established between the occurrence of the signals and polarcap absorption. Finally, a possible analogy is drawn between hm emissions and VLF emissions as observed by other workers, and a model is presented which may lead to the understanding of generation of hm emissions. The instrumentation associated with the collection of hydromagnetic- emission data during the period February to December 1960 is described. Periods during which data were recorded are tabulated. The development of the specific instrumentation used during November 18 to 21 to obtain the data is described. Abstracts are provided of publications covering work done at Lockheed in closely related fields, and partially supported by the present contract. (auth)

• Research Organization: Lockheed Aircraft Corp. Missiles and Space Div., Sunnyvale, Calif.
• NSA Number: NSA-16-011072
• OSTI ID: 4809288
• Report Number(s): LMSD-894814; AFCRL-198; AD-260
• Country of Publication: United States
• Language: English

Related Subjects

ABSORPTION
ALFVEN WAVES
ANTARCTICA
ARCTIC REGIONS
BIBLIOGRAPHY
DIAGRAMS
EARTH
ELECTROMAGNETIC WAVES
EMISSION
FREQUENCY
GEOPHYSICS
HYDROMAGNETIC WAVES
INSTRUMENTS
IONOSPHERE
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MEASURED VALUES
MOTION
OSCILLATIONS
PHYSICS
PLASMA WAVES
POLAR-CAP ABSORPTION
SAMPLING
SIGNALS
SUN
TABLES
VARIATIONS