Power spectra of geomagnetic fluctuations between 0.4 and 40 Hz.
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Authors
Clayton, Frederick William
Subjects
Advisors
Heinz, O.
Date of Issue
1979-06
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
Power spectra of the fluctuations of the geomagnetic field
were obtained for the frequency range of 0,4 - 40 Hz using an
optically pumped Cesium vapor magnetometer. The measurements
were made at Monterey, California in May, 1979. The spectra
display a gradual decrease in slope at low frequencies with
zero slope occurring between approximately 5 Hz and 15 Hz
followed by a slight increase in slope. Data was collected
at local midnight (0000-0200) , local morning (0800-1000) and
local afternoon (1600-1800), The morning and afternoon spectra
exhibit what is believed to be a Schumann resonance peak
at 8.0 Hz. A peak at 2.2 Hz and its first harmonic (4.4 Hz)
were also observed, but are believed to be a man-made phenomenon
or a sensor related instrumentation effect. Considerable
high frequency disturbances (20-40 Hz) were observed
around local midnight and are believed to be ELF "Sf erics".
A comparison between a magnetically disturbed day (Fredericksburg
Index of 7+) and a quiet day (Fredericksburg Index of
2+) at the same time period (0800-1000) showed a difference
of 7-9 dB in power spectral density.
Type
Thesis
Description
Series/Report No
Department
Physics
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
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Citation
Distribution Statement
Approved for public release; distribution is unlimited.