Low Frequency Geomagnetic Fluctuations (0.025 to 20 Hz) on the Floor of Monterey Bay PDF Download

Author: Morgan P. Ames
Publisher:
ISBN:
Category : Geomagnetism
Languages : en
Pages : 226

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Author: Gerald R. McDevitt
Publisher:
ISBN:
Category :
Languages : en
Pages : 112

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A coil antenna consisting of approximately 6000 turns of copper wire was used to measure the horizontal component of fluctuations of the earth's magnetic field on the floor of Monterey Bay in water depth of approximately 50 meters. The results indicate that the power spectral density of the fluctuations varies from 10(nT)-sq/Hz at 0.04 Hz to 0.000001(nT)-sq/Hz at 25 Hz, a monotonic decrease of about 6 dB/octave, except in the 8-20 Hz region where the Schuman resonances occur. While the sensitivity of the equipment was insufficient to measure the vertical component of the fluctuation we can put an upper limit of 0.001(nT)-sq/Hz at 1 Hz and 0.000001(nT)-sq/Hz) at 10 Hz on the magnitude of this component. The same sensor was also used to measure various components of the field fluctuations at a remote land site (Chew's Ridge). In the frequency range observed the general shape of the spectra was similar to those obtained at sea. However, a strong azimuthal variation at certain frequencies was noted in the land data. The possibility that these directional signals are of man made origin cannot be excluded at this time. (Author).

Author: Edmund J. Chaffee
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Using a Cs vapor magnetometer, we observed fluctuations of the total magnetic field in the .01 Hz to 3 Hz frequency range on the floor of Monterey Bay, California. Fourteen hours of data were recorded over a period of six months in 1979 at several depths from 30 to 300 meters. A small, inexpensive recording system was designed and manufactured having a noise floor below 0.001 nTin the frequency range of interest. Data analysis includes an ocean wave/geomagnetic fluctuation comparison along with a qualitative analysis of the power spectra of the fourteen hours of geomagnetic fluctuation data. Typical geomagnetic fluctuation spectrum levels were found to be about 1 (nT)-sq/Hz at .01 Hz. As the frequency increased, the magnitude of the spectrum decreased to approximately 0.00001 (nT)-sq/Hz at 3 Hz. Correlation between ocean wave period and peaks in the geomagnetic fluctuation spectra was observed. (Author).

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1174

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Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 228

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Author: J.J. Lielpeteris
Publisher: Springer Science & Business Media
ISBN: 9400909993
Category : Science
Languages : en
Pages : 454

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Liquid metal MHO is within the scope of two series of international conferences. One is the International Congress on "MHD Power Generation", held every four years, which includes technical and economical aspects as well as scientific questions. The other if the Beer-Sheva Seminar on "MHO Flows and Turbulence", held every three years in Israel. In addition to these well established meetings, an IUTAM Symposium was previously organized in Cambridge (UK) in 1982 on "Metallurgical Applications of MHD" by the late Arthur Shercliff. It was focussed on a very specific subject developing radiply from the middle of the 1970's. The magnetic field was generally AC, including frequencies high enough for the skin-depth to be much smaller than the typical length scale of the liquide pool. And the development of new technologies, or the improvement of existing ones, was the main justification of most of the researches presented and discussed. Only two participants from Eastern countries attended this Symposium. By the middle of the 1980's we felt that on this very same topic ideas had reached much more maturity than in 1982. We also realized that a line of research on MHD flows related to fusion reactors (tokamaks) was developing significantly, with particular emphasis on flows at large interaction parameter.

Author: Katherine B. Kidwell
Publisher:
ISBN:
Category : Meteorological satellites
Languages : en
Pages : 424

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Author: Masahiro Wakatani
Publisher: Oxford University Press, USA
ISBN: 9780195078312
Category : Language Arts & Disciplines
Languages : ko
Pages : 462

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This monograph describes plasma physics for magnetic confinement of high temperature plasmas in nonaxisymmetric toroidal magnetic fields or stellarators. The techniques are aimed at controlling nuclear fusion for continuous energy production. While the focus is on the nonaxisymmetric toroidal field, or heliotron, developed at Kyoto University, the physics applies equally to other stellarators and axisymmetric tokamaks. The author covers all aspects of magnetic confinement, formation of magnetic surfaces, magnetohydrodynamic equilibrium and stability, single charged particle confinement, neoclassical transport and plasma heating. He also reviews recent experiments and the prospects for the next generation of devices.

Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309478219
Category : Nature
Languages : en
Pages : 341

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Whether the result of an oil well blowout, vessel collision or grounding, leaking pipeline, or other incident at sea, each marine oil spill will present unique circumstances and challenges. The oil type and properties, location, time of year, duration of spill, water depth, environmental conditions, affected biomes, potential human community impact, and available resources may vary significantly. Also, each spill may be governed by policy guidelines, such as those set forth in the National Response Plan, Regional Response Plans, or Area Contingency Plans. To respond effectively to the specific conditions presented during an oil spill, spill responders have used a variety of response optionsâ€"including mechanical recovery of oil using skimmers and booms, in situ burning of oil, monitored natural attenuation of oil, and dispersion of oil by chemical dispersants. Because each response method has advantages and disadvantages, it is important to understand specific scenarios where a net benefit may be achieved by using a particular tool or combination of tools. This report builds on two previous National Research Council reports on dispersant use to provide a current understanding of the state of science and to inform future marine oil spill response operations. The response to the 2010 Deepwater Horizon spill included an unprecedented use of dispersants via both surface application and subsea injection. The magnitude of the spill stimulated interest and funding for research on oil spill response, and dispersant use in particular. This study assesses the effects and efficacy of dispersants as an oil spill response tool and evaluates trade-offs associated with dispersant use.

Author: Jules Aarons
Publisher:
ISBN:
Category : Geostationary satellites
Languages : en
Pages : 48

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Amplitude fluctuations produced by small irregularities in electron density in the F-layer of the ionosphere (at 300 to 400 km height) can be a problem to communication and navigation systems in the VHF-UHF range. Recent measurements, primarily by AFCRL, are shown with emphasis on results at high and equatorial latitudes. At high latitudes an irregularity region exists whose lower boundary reaches 57 degrees invariant latitude near midnight. During magnetic storms the boundary descends to lower latitudes and the fading becomes deeper. Over the polar cap scintillations are somewhat diminished. When observing synchronous satellites through the irregularity region, deep and fast fading is frequently seen, with fade rates to one per second. Irregularities produce deep scintillations in the VHF range plus or minus 15 degrees from the geomagnetic equator. In equatorial regions maximum occurrence of high level scintillations takes place between 2100 and 2400 local time during the equinoxes; a minimum occurrence is observed during the solstices. When the sunspot number decreases, the equatorial irregularity region spreads and becomes larger. The data for various latitudes has been placed in statistical form, that is, distribution of amplitudes for 15-min samples as well as for periods of 1 yr and longer. (Author).