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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Interplanetary magnetic field data book

An interplanetary magnetic field (IMF) data set is presented that is uniform with respect to inclusion of cislunar IMF data only, and which has as complete time coverage as presently possible over a full solar cycle. Macroscale phenomena in the interplanetary medium (sector structure, heliolatitude variations, solar cycle variations, etc.) and other phenomena (e.g., ground level cosmic-ray events) for which knowledge of the IMF with hourly resolution is necessary, are discussed. Listings and plots of cislunar hourly averaged IMP parameters over the period November 27, 1963, to May 17, 1974, are presented along with discussion of the mutual consistency of the IMF data used herein. The magnetic tape from which the plots and listings were generated, which is available from the National Space Science Data Center (NSSDC), is also discussed.

King, J. H.↗
NASA NTRS1989

Small scale irregularities in Comet Halley's plasma mantle - An attempt at self-consistent analysis of plasma and magnetic field data

VEGA-1 measurements of the plasma density and magnetic field in the coma of Comet Halley show characteristic signatures over a significant portion of the outbound pass. It is found that the assumption that there is a balance between the thermal and magnetic pressures in these features can be used to obtain estimates of the plasma temperature as a function of distance from the nucleus. These estimates indicate that the ions cool from about 1.5 x 10 to the 6th K at 10 to the 5th km to 2 x 10 to the 5th K at 5 x 10 to the 4th km. The technique used here represents a novel approach whereby temperature measurements can be made in situations where only plasma density and magnetic field data are available.

Vaisberg, O. L.↗
DOE OSTI2024

Analysis on Evaluations of Monterey Bay Aquarium Research Institute’s Wave Energy Converter’s Field Data Using WEC-Sim and Gazebo: A Simulation Tool Comparison

Although many studies have validated wave energy converter (WEC) numerical models against scaled prototype experimental data, there remains a notable lack of validation using data from full-scale deployed WECs. This paper compares two numerical models of Monterey Bay Aquarium Research Institute’s Wave Energy Converter (MBARI-WEC), a two-body point absorber with an electro-hydraulic power take-off system (PTO). The models are implemented in WEC-Sim/Simscape and Gazebo Simulator. A statistical analysis of the models was performed, and field results were obtained to compare the models’ accuracy in predicting the RMS piston velocity, RMS motor speed, and mean electric power compared to field data for 56 observations across varying sea states. The Gazebo model demonstrated a closer agreement across all three parameters for a majority of the observations. When compared to the field data, the Gazebo and WEC-Sim models exhibited average mean electric power overestimations of 13% and 22%, respectively.

16 TIDAL AND WAVE POWER↗
DOE OSTI2024

Electric Field Data from the North Slope of Alaska

File contains raw as well as calibrated electric field values (V/m) from two CS110 electric field meters. The file also contains raw 2-m U and V winds at the same site. The sampling rate is 1Hz. All files contain raw electric field data, as well as calibrated values to a one week ground-based calibration setup. During this week, simultaneous upward-facing ground based electric field measurements were taken alongside the two downward facing instruments on the pole (CS110-3 at 2m and CS110-2 at 5m). Slopes and intercepts were calculated and applied to the values influenced by the pole to convert the raw data to calibrated values. These calibrated values are absolute electric field measurements. There are no missing data codes. The missong data is not included in the files, and thus any files with missing data will be shorter than the normal 86,400 values. In July 2023, the CS110-3 was replaced with an identical instrument named CS110-8, and the CS110-2 was replaced with an identical instrument called CS110-9. All the variable names remained consistent and the same.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1974

Investigations of cosmic ray anisotropies and their relationship to concurrent magnetic field data

Investigations of cosmic ray anisotropies and their relationship to concurrent magnetic field data are reported. These investigations range in scope from the examination of data very late in the decay phase of a solar particle event where long term (approximately 6 hour) averages are used and definite interplanetary effects sought after to an examination of the change in low energy particle anisotropy as the satellite approaches the bow shock and the magnetopause.

Allum, F. R.↗
NASA NTRS1972

Ogo 5 magnetic-field data near the earth's bow shock - A correlation with theory.

Magnetic-field data obtained in the earth's bow-shock region with a high-resolution triaxial fluxgate magnetometer aboard the Ogo 5 satellite have been correlated with a theory of Tidman and Northrop (1968). These authors have shown that either of two hypotheses about the nature of low-frequency magnetic waves could be invoked to explain previous observations. We have observed exponentially decaying upstream waves that are consistent with only one of these hypotheses. This observation allows use of the theory to infer the local shock velocity and frequency of driving currents within the shock. This method of finding the shock velocity is less sensitive to errors in the plasma parameters than is the method based on the Rankine-Hugoniot relations.

Guha, J. K.↗
NASA NTRS1999

A Review of Magnetic Anomaly Field Data for the Arctic Region: Geological Implications

Due to its inaccessibility and hostile physical environment remote sensing data, both airborne and satellite measurements, has been the main source of geopotential data over the entire Arctic region. Ubiquitous and significant external fields, however, hinder crustal magnetic field studies. These potential field data have been used to derive tectonic models for the two major tectonic sectors of this region, the Amerasian and Eurasian Basins. The latter is dominated by the Nansen-Gakkel or Mid-Arctic Ocean Ridge and is relatively well known. The origin and nature of the Alpha and Mendeleev Ridges, Chukchi Borderland and Canada Basin of the former are less well known and a subject of controversy. The Lomonosov Ridge divides these large provinces. In this report we will present a summary of the Arctic geopotential anomaly data derived from various sources by various groups in North America and Europe and show how these data help us unravel the last remaining major puzzle of the global plate tectonic framework. While Magnetic anomaly data represent the main focus of this study recently derived satellite gravity data (Laxon and McAdoo, 1998) are playing a major role in Arctic studies.

Taylor, Patrick T.↗
NASA NTRS1999

A Review of Magnetic Anomaly Field Data for the Arctic Region: Geological Implications

Due to its inaccessibility and hostile physical environment remote sensing data, both airborne and satellite measurements, has been the main source of geopotential data over the entire Arctic region. Ubiquitous and significant external fields, however, hinder crustal magnetic field studies These potential field data have been used to derive tectonic models for the two major tectonic sectors of this region, the Amerasian and Eurasian Basins. The latter is dominated by the Nansen-Gakkel or Mid-Arctic Ocean Ridge and is relatively well known. The origin and nature of the Alpha and Mendeleev Ridges, Chukchi Borderland and Canada Basin of the former are less well known and a subject of controversy. The Lomonosov Ridge divides these large provinces. In this report we will present a summary of the Arctic geopotential anomaly data derived from various sources by various groups in North America and Europe and show how these data help us unravel the last remaining major puzzle of the global plate tectonic framework. While magnetic anomaly data represent the main focus of this study recently derived satellite gravity data are playing a major role in Arctic studies.

Taylor, Patrick T.↗
NASA NTRS1994

Analysis of magnetic field data from Pioneer Venus orbiter

The subject grant (NAG 2-501) supported the analysis of magnetic field data from the Pioneer Venus orbiter for the period 10/1/87 to 9/30/94. During that period, 188 papers were contributed to scientific meetings that either analyzed the magnetometer data or used the data as part of the analysis of a scientific problem. Further, 107 papers were published in research journals and books. The magnetic moment of Venus was described. Venus was found to be essentially devoid of any intrinsic magnetic field. There was evidence though for the presence of lightning in the Venus atmosphere. The altitude distribution of impulsive signals in the night atmosphere was mapped and geographic clusters were found, most probably associated with local time ordering. A new means to create flux ropes in the ionosphere was postulated. On the nightside, ionospheric holes, ionospheric clouds, and tail rays were studied. The subsolar ionopause and the magnetic barrier were examined as was the altitude asymmetry of the ionopause, properties of the magnetosheath, and location of the bow shock upstream waves.

Russell, Christopher T.↗
NASA NTRS1982

Interactive analysis of magnetic field data

The development of an interactive graphics system for speeding up the identification and analysis of magnetic field data received from spacecraft is described. A flat file system was designed with a standard header file which contained space for user notes. The system featured a minicomputer with the capacity to handle up to 20 remote terminal requests simultaneously. Time series of vector field analyses were displayed and analyzed using the B-analysis (BANAL) program, while TANAL was devised to handle trajectory analyses. BANAL permits calculations of rotations, hodograms, and power spectra, and TANAL features time series, altitude profile, and vector trajectory plots. Subsequent programs for cross-correlations and filtering are indicated.

Russell, C. T.↗
NASA NTRS1972

Coastal environment of the Beaufort Sea from field data and ERTS-1 imagery, summer 1972

The author has identified the following significant results. An extensive field program during the spring and summer in the coastal Beaufort Sea test site has been completed using a wide variety of sensing techniques. Reduction of field data and ERTS-1 image analysis have shown the coastal environment to be complexly influenced by unique processes, most of which involve or are related to sea ice. Active sedimentologic processes along the Arctic coast are set in motion by the melting, flooding, and eventual overflow of rivers onto the sea ice. It is now apparent that only minor amounts of sediment are transported offshore at this stage; however, scouring of the bottom is significant beneath the strudels (drain holes) which develop in the fast ice canopy in the region of overflow. Areal salinity and turbidity patterns together with ERTS-1 imagery confirm a consistent influx of colder, clearer, saltier water towards the coast just east of the Colville River. Strong (up to 3 knots) bidirectional but intermittent currents often manifest themselves in imagery and aerial photographs as wakes behind grounded ice. Ice movement vectors generated from repetitive images indicate that ice drift is closely associated with wind direction, especially in shallow bays, and displacements of 4-22 kilometers were noted in 24 hours.

Reimnitz, E.↗
NASA NTRS1981

Artificial stereo presentation of meteorological data fields

The innate capability to perceive three-dimensional stereo imagery has been exploited to present multidimensional meteorological data fields. Variations on an artificial stereo technique first discussed by Pichel et al. (1973) are used to display single and multispectral images in a vivid and easily assimilated manner. Examples of visible/infrared artificial stereo are given for Hurricane Allen and for severe thunderstorms on 10 April 1979. Three-dimensional output from a mesoscale model also is presented. The images may be viewed through the glasses inserted in the February 1981 issue of the Bulletin of the American Meteorological Society, with the red lens over the right eye. The images have been produced on the interactive Atmospheric and Oceanographic Information Processing System (AOIPS) at Goddard Space Flight Center. Stereo presentation is an important aid in understanding meteorological phenomena for operational weather forecasting, research case studies, and model simulations.

Hasler, A. F.↗
NASA NTRS1995

Locations of termination shock and heliopause based on Voyager plasma and magnetic field data

The locations of the termination shock and the heliopause are studied taking into account the effects of pickup protons. The study uses available plasma and magnetic field data from Voyagers over a 14-year period (1978-1991) and Voyager observation of the 1992-93 radio emission event. Outside 30 AU, pickup protons have a significant influence on dynamical structures of the outer heliosphere. The solar wind is treated as a mixture of electrons, solar wind protons, and interstellar pickup protons. If the magnitude of the interstellar magnetic field B(sub int) is given, one can quantitatively study the motion and location of the termination shock. The location is anti-correlated with the sun spot number and the shock has an average speed of approx. 24 km/s. Because B(sub int) is poorly known, additional information is needed in studying the termination shock. Cummings, et al. have used observations of anomalous cosmic rays to estimate the location of the shock. The observations of the 1991 GMIR and GMIR shock and the 1992-93 radio emission event provide another handle for the study of the termination shock and the heliopause. After its penetration through the termination shock, the GMIR shock continued to propagate in the subsonic region of the solar wind and eventually interacted with the heliopause. This interaction produces a transmitted shock propagating outward in the interstellar medium and a reflected shock propagating inward toward the sun in the subsonic solar wind. The plasma frequencies behind the reflected and the transmitted shock can be, respectively, responsible for the 2- and 3-kHz radio emissions. Taking into account the effects of pickup protons we found that the average locations of the termination shock and the heliopause in 1991-92 are at approximately 66 AU and 150 AU, respectively.

Whang, Y. C.↗
DOE OSTI2024

Field Study of Nighttime Leakage Currents in Bifacial PV Modules: Correlation with Atmospheric Electric Field Data

Leakage currents measured on PV modules in the field originate from a potential difference between the modules' frame and the cells. They can be a relative indicator of Potential-Induced Degradation (PID) severity, especially when comparing the same module design in a different environment. As modules are not operating at night, no leakage current should be observed but our team has reported several events of nighttime leakage currents on bifacial PV modules. These events have been firstly observed during a thunderstorm that are characterized by strong atmospheric electrical field values. This lead us to believe that nighttime leakage currents could originate from the atmospheric electric charges. In this paper, we correlate nighttime leakage currents measured on bifacial PV modules with field mill data to identify the origin of nighttime leakage currents. Our results show that so far, no leakage currents at night occur when the atmospheric electric field is between 0 and 150–200 V/m (standard value for fair weather). As soon as the atmospheric electric field is out of this range, leakage currents are observed with or without rain involved. This suggests a transport of charged particles from the atmosphere to the modules' frame. A combination of heavy rain with strong atmospheric electric field results into high nighttime leakage currents with a magnitude up to 8 times higher than what observed during the day with -1500V applied. This is explained by an easier transport of the charged particles through the water droplets. Based on these results, leakage currents observed during the day might not be only due to the inherent potential difference between the frame and the cells depending on the atmospheric electric field activity. We believe that it should be taken into account in PID studies.

14 SOLAR ENERGY↗