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Results for “MAGNETIC SURVEY”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Study of gravity and magnetic anomalies using MAGSAT data

The results of modeling satellite-elevation magnetic and gravity data using the constraints imposed by near surface data and seismic evidence shows that the magnetic minimum can be accounted for by either an intracrustal lithologic variation or by an upwarp of the Curie point isotherm. The long wavelength anomalies of the NOO's-vector magnetic survey of the conterminous U.S. were contoured and processed by various frequency filters to enhance particular characteristics. A preliminary inversion of the data was completed and the anomaly field calculated at 450 km from the equivalent magnet sources to compare with the POGO satellite data. Considerable progress was made in studing the satellite magnetic data of South America and adjacent marine areas. Preliminary versions of the 1 deg free-air gravity anomaly map (20 m gal contour interval) and the high cut (lambda approximately 8 deg) filtered anomaly maps are included.

Braile, L. W.↗
NASA NTRS1980

Magsat scientific investigations

The Magsat spacecraft is providing the first global, vector magnetic survey. Investigations using the Magsat data are being carried out by scientists at NASA's Goddard Space Flight Center, at the U.S. Geological Survey of the Department of the Interior and by 32 selected investigators. Nineteen of the investigators are from the United States and 13 are from various foreign nations. The investigations described fall into four categories; (1) geomagnetic field modeling; (2) crustal magnetic anomaly studies; (3) investigations of the inner Earth: the core, mantle and core-mantle interface; and (4) studies of external current systems.

Langel, R. A.↗
NASA NTRS1988

The geomagnetic field at 1982 from DE-2 and other magnetic field data

Data from the DE-2 spacecraft are combined with data from the Magsat spacecraft and data from magnetic observatories and magnetic surveys to derive a geomagnetic field model for the period from May 1979 to May 1983. The model is an extension of the Goddard Space Flight Center (12/83) model. The model includes a solution for parameters representing the noncore field, or anomaly bias, at each observatory in the Project Magnet program. A table of these anomalies is presented. The results from this model are compared with those from the IGRF1980 (Peddie, 1982) and the IGRF1987 (Barraclough, 1987).

Langel, R. A.↗
NASA NTRS1971

Geomagnetic survey by the polar-Orbiting Geophysical Observatories.

Summary of reduced data from the polar Orbiting Geophysical Observatories OGO 2 and 4, spanning the time period from Oct. 14, 1965 to the end of 1967. A brief discussion of the accuracy of the observations is followed by a description of the data extent. It is shown that the quantity of data acquired by the OGO magnetometers far exceeds the total for all other magnetic survey sources. Data acquisition for only about a two-week interval gives virtually complete global coverage. Procedures and considerations underlying the data analysis performed are discussed. Suggestions for further work are presented.

Cain, J. C.↗
DOE OSTI2024

A Deep Learning Based Framework to Identify Undocumented Orphaned Oil and Gas Wells from Historical Maps: A Case Study for California and Oklahoma

Undocumented Orphaned Wells (UOWs) are wells without an operator that have limited or no documentation with regulatory authorities. An estimated 310,000 to 800,000 UOWs exist in the United States (US), whose locations are largely unknown. These wells can potentially leak methane and other volatile organic compounds to the atmosphere, and contaminate groundwater. In this study, we developed a novel framework utilizing a state-of-the-art computer vision neural network model to identify the precise locations of potential UOWs. The U-Net model is trained to detect oil and gas well symbols in georeferenced historical topographic maps, and potential UOWs are identified as symbols that are further than 100 m from any documented well. A custom tool was developed to rapidly validate the potential UOW locations. We applied this framework to four counties in California and Oklahoma, leading to the discovery of 1301 potential UOWs across >40,000 km 2 . We confirmed the presence of 29 UOWs from satellite images and 15 UOWs from magnetic surveys in the field with a spatial accuracy on the order of 10 m. This framework can be scaled to identify potential UOWs across the US since the historical maps are available for the entire nation.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1972

Gosses Bluff impact structure, Australia.

A comprehensive study has been carried out of the Gosses Bluff structure in Central Australia, which is a typical cryptoexplosion structure. The study included detailed geologic mapping, and seismic reflection and refraction, gravity, aeromagnetic, and ground magnetic surveys. It is concluded that the structure is an eroded crater formed by a single nearly instantaneous shock event, and that the event can be explained only by impact.

Milton, D. J.↗
NASA NTRS1974

The oceanic islands - Azores

A presentation is made of the known geological, geophysical, and geochemical data on the Azores. The regional setting of the islands is described; under the geological heading, surface geology and petrochemistry are discussed; and paleomagnetism, marine magnetic surveys, gravity, seismology, and heat flow are treated in the geophysics category. A model for the origin of the Azores is constructed on the basis of these observations.

Ridley, W. I.↗
NASA NTRS2003

Basaltic Magmatism: The Dominant Factor in the Petrologic and Tectonic Evolution of the Earth

Silicate bodies such as the Moon, Mars, probably Mercury, and possibly Venus, appear to have evolved in three main stages: a first (felsic) differentiation, a late heavy bombardment, and a second (basaltic) differentiation. It has been proposed that the Earth underwent a similar sequence. This paper argues that the second differentiation, basaltic magmatism, has dominated the petrologic and tectonic evolution of the Earth for four billion years. A global andesitic crust, formed during and after accretion of the planet, was disrupted by major impacts that triggered mantle upwelling and sea-floor spreading about 4 billion years ago. The oceanic crust collectively has since been formed by basaltic volcanism, from spreading centers and mantle plumes. However, the continental crust has also been greatly affected. Basaltic underplating has promoted anatexis and diapiric intrusion of granitoids in granite-greenstone terrains, as well as providing heat for regional metamorphism. Basaltic intrusions, such as the Nipissing diabase of the Sudbury area, have added to the thickness of continental crust. Satellite magnetic surveys suggest that there are more such basaltic intrusions than previously realized; examples include the Bangui anomaly of central Africa and the Kentucky anomaly. Basaltic overplating from mafic dike swarms has repeatedly flooded continents; had it not been for erosion, they would be covered with basalt as Venus is today. The tectonic effects of basaltic volcanism on continents have only recently been realized. The World Stress Map project has discovered that continents are under horizontal compressive stress, caused by push from mid-ocean ridges, i.e., by basaltic volcanism. The stress fields are generally uniform over large intraplate areas, and could contribute to intraplate tectonism. Seafloor spreading has demonstrably been effective for at least 200 million years, and ridge push thus a contributor to tectonic activity for that long. Collectively, the petrologic and tectonic evolution of the Earth has been dominated for about 4 billion years by the 'second differentiation,' i.e., by basaltic magmatism.

Lowman, Paul D., Jr.↗
NASA NTRS2021

A Century of Tidal Variability in the North Pacific Extracted from Hourly Geomagnetic Observatory Measurements at Honolulu

Previous analyses of hourly tide-gauge data taken at Honolulu since 1905 have shown that both sea level and the amplitude of the tides have increased synchronously over time, and a process has been proposed whereby the common cause is an increase in ocean temperature. Validation with independent data of this change in tides, as well as the proposed cause, has been lacking Ocean tides also generate magnetic fields that reach far outside the ocean, and tidal signals are clearly seen in the hourly data since 1905 from the Honolulu geomagnetic observatory. Here, it is found that the tidal amplitudes have increased synchronously in the tide-gauge and magnetic records, providing independent support for the previous results. Further information about the changing ocean is likely contained in the historical data from geomagnetic observatories as well as the global coverage of modern satellite magnetic surveys.

Robert H Tyler↗
DOE OSTI2025

Project FELICIA - A probe to survey the RHIC magnet beampipe diameter for EIC beam screen insertion

The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will reuse many of the existing superconducting (SC) magnets of the RHIC storage rings. To comply with the beamline vacuum requirements in more demanding operational scenarios, the beampipe of the RHIC SC magnets will be equipped with low surface impedance, low secondary electron yield (SEY) beam screens. The installation of these beam screens will be done with the SC magnets as installed today, thus making it a critical operation for a timely EIC installation. The beam screen inner dimensions must be maximized to retain enough aperture to the beam. On the other hand, keeping enough clearance between the screen and the beampipe is critical to ensure a smooth beam screen installation. A survey probe was designed and built to measure the inner diameter of several RHIC SC magnets in-situ and provide critical data for the beam screen design optimization. This paper reports on the design of the probe and the results from the survey campaign.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Finding evidence for inflation and the origin of galactic magnetic fields with CMB surveys

The origin of the μG magnetic fields observed in galaxies is unknown. One promising scenario is that magnetic fields generated during inflation, larger than 0.1 nG on Mpc scales, were adiabatically compressed to μG strengths in galaxies during structure formation. Thus, detecting a scale-invariant primordial magnetic field (PMF) above 0.1 nG on Mpc scales just after recombination would indicate an inflationary origin of galactic magnetic fields. Furthermore, this would also provide compelling evidence that inflation occurred since only an inflationary mechanism could generate such a strong, scale-invariant magnetic field on Mpc scales. In contrast, constraining the scale-invariant PMF strength to be below 0.1 nG would imply an inflationary scenario is not the primary origin, since such weak PMFs cannot be amplified enough via adiabatic compression to produce the strength of the galactic fields we observe today. We find that measurements of anisotropic birefringence by future CMB surveys will be able to improve the sensitivity to Mpc-scale inflationary PMFs by an order of magnitude, and, in particular, that CMB-HD would lower the upper bound to 0.072 nG at the 95% C.L., which is below the critical 0.1 nG threshold for ruling out a purely inflationary origin. If inflationary PMFs exist, we find that a CMB-HD survey would be able to detect them with about 3σ significance or higher, providing evidence for inflation itself.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

A survey of pedestal magnetic fluctuations using gyrokinetics and a global reduced model for microtearing stability

This article presents a global reduced model for slab-like microtearing modes (MTMs) in the H-mode pedestal, which reproduces distinctive features of experimentally observed magnetic fluctuations, such as chirping and discrete frequency bands at noncontiguous mode numbers. Our model, importantly, includes the global variation of the diamagnetic frequencies, which is necessary to reproduce the experimental observations. The key insight underlying this model is that MTM instability is enabled by the alignment of a rational surface with the peak in the profile of the diamagnetic frequency. Conversely, MTMs are strongly stabilized for toroidal mode numbers for which these quantities are misaligned. This property explains the discrete fluctuation bands in several DIII-D and JET discharges, which we survey using our reduced model in conjunction with global gyrokinetic simulations. A fast yet accurate reduced model for MTMs enables rapid interpretation of magnetic fluctuation data from a wide range of experimental conditions to help assess the role of MTM in the pedestal.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1992

Survey of transient magnetic field events in the dayside magnetosphere

Data acquired with AMPTE/CCE are employed to investigate transient magnetic field events (TMFEs) in the dayside magnetosphere. TMFEs are found to occur more frequently near the magnetopause than deep in the magnetosphere, and the amplitude of a TMFE increases as the spacecraft comes closer to the magnetopause. It is inferred that they are generated at the magnetopause. From the MLT dependence of the rotational polarity of the transverse magnetic field perturbation, it is suggested that TMFE structures move longitudinally away from the noon meridian. Latitudinal motion away from the equator is also inferred from the latitudinal dependence of the occurrence rates of the standard and reverse events. The motion of TMFEs is tailward in both azimuthal and north-south directions. It is suggested that TMFEs carry oppositely directed twin field-aligned currents, separated in the direction perpendicular to the direction of motion and having the same current intensity.

Kawano, H.↗
NASA NTRS1997

A Combined MG II/CA II Survey of Stellar Magnetic Activity in the Solar Neighborhood

We use nearly contemporaneus low-resolution IUE observations of Mg II h + k emission and Mount Wilson Observatory Ca II H + K S indices for 33 pairs of observations of lower main sequence stars to formulate a relationship that will permit accurate predictions of S values as a function of (B - V) color and Mg II h + k flux. The resulting relationship is useful because it will extend the set of solar neighborhood stars for which a uniform estimate of chromospheric activity is available to include stars that are not observable from Mount Wilson as well as providing additional estimates of activity levels for stars that are on the Mount Wilson HK Project observing list.

Wicklund, B. M.↗
NASA NTRS1981

The enigma of lunar magnetism

Current understandings of the nature and probable origin of lunar magnetism are surveyed. Results of examinations of returned lunar samples are discussed which reveal the main carrier of the observed natural remanent magnetization to be iron, occasionally alloyed with nickel and cobalt, but do not distinguish between thermoremanent and shock remanent origins, and surface magnetometer data is presented, which indicates small-scale magnetic fields with a wide range of field intensities implying localized, near-surface sources. A detailed examination is presented of orbital magnetometer and charged particle data concerning the geologic nature and origin of magnetic anomaly sources and the directional properties of the magnetization, which exhibit a random distribution except for a depletion in the north-south direction. A lunar magnetization survey with global coverage provided by a polar orbiting satellite is suggested as a means of placing stronger constraints on the origin of lunar crustal magnetization.

Hood, L. L.↗