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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Solar modulation of atmospheric electrification through variation of the conductivity over thunderstorms

It is suggested that variations of the current in the global atmospheric electrical circuit can be produced through regulation of the resistance between the tops of thunderclouds and the ionosphere. Long- and short-term changes in the conductivity of this region occur due to changes in the ionization rate resulting from solar activity. Previous suggestions that the phenomena might be due to conductivity variations in the fair weather part of the world or an influx of space charge to the upper atmosphere are discussed and considered unlikely. It might be possible to test the proposed mechanism by measuring the temporal variation of the ionospheric potential during distributed solar periods. Another approach would be to measure simultaneously the variation in ionization rate and electric current over thunderstorms. Several ways in which changes in atmospheric electrification might influence other meteorological phenomena are mentioned.

Markson, R.↗
NASA NTRS1972

Solar modulation of galactic cosmic rays. 3: Implications of the Compton-Getting coefficient

Spectra of modulated galactic cosmic rays are expressed in terms of the Compton-Getting coefficient C. This parameter can reveal the energy range over which the force field approximation is valid, and the range where convection effects dominate those of diffusion. A value of C near zero over an extended low energy range implies that the radial gradient at low energies can not be large. This small gradient may imply that the diffusion coefficient increases beyond 1 AU less rapidly than proportionally to heliocentric radial distance, and/or there is essentially no scattering for a sizeable distance from the Sun to earth. The behavior of C with rigidity (or energy) is discussed in terms of the omnidirectional distribution function f sub zero. Contours of constant f sub zero in the heliocentric distance vs rigidity plane are useful for illustrating the mean rigidity loss experienced by cosmic rays in the interplanetary medium.

Fisk, L. A.↗
NASA NTRS1973

A study of cosmic-ray positron and electron spectra in interplanetary and interstellar space and the solar modulation of cosmic rays

The differential energy spectra of cosmic-ray positrons and negatrons with energies between approximately 11 and 1500 MeV was measured during the period 1968-1971 using a balloon-borne magnetic spectrometer. These measurements fill a gap in the previously existing data and permit the determination of the interstellar spectra of cosmic-ray positrons and electrons. Knowledge of these spectra provides a crucial tool for studies of the distribution and density of matter and magnetic fields in the interstellar medium and the origin and dynamics of energetic particles contained in the fields. The differential energy spectrum of interstellar electrons may be represented as a power-law, j alpha T to the -1.8 power for 100 MeV approximately T approximately 2 GeV, but must flatten considerably at lower energies. From the measured electron charge composition, it is concluded that the majority of cosmic-ray electrons with energies above approximately 10 MeV originate in primary sources.

Cummings, A. C.↗
NASA NTRS1974

Analytic approximations in the study of the solar modulation of electrons

Numerical solutions to the transport equation of galactic cosmic rays in the interplanetary medium have been used to investigate the applicability of commonly used approximate analytic solutions for electrons (10 MeV to 10 GeV). We find that for a given cosmic-ray diffusion coefficient the force-field approximation is in reasonable agreement with the numerical solution at energies above 200 MeV, but deviates significantly at lower energies, depending on the shape of the interstellar electron spectrum. The diffusion-convection approximation agrees generally with the numerical solution within a factor of 2 over the entire energy range.

Cummings, A. C.↗
NASA NTRS1979

Automated Solar Module Assembly Line

The gathering of information that led to the design approach of the machine, and a summary of the findings in the areas of study along with a description of each station of the machine are discussed. The machine is a cell stringing and string applique machine which is flexible in design, capable of handling a variety of cells and assembling strings of cells which can then be placed in a matrix up to 4 ft x 2 ft. in series or parallel arrangement. The target machine cycle is to be 5 seconds per cell. This machine is primarily adapted to 100 MM round cells with one or two tabs between cells. It places finished strings of up to twelve cells in a matrix of up to six such strings arranged in series or in parallel.

Bycer, M.↗
NASA NTRS1981

Wind-simulation tester for solar modules

Tester induces cyclic pressure loads across module surface, guaranteeing its mechanical integrity. Module to be tested is sandwiched between stiffened aluminum layers covered with rubber sheets. Automatic front and back pressure loading is cycled by pneumatic system on separate stand. Relief valves prevent overpressuring. Fixture operates at high speed, completing cycle in 5 seconds, and typically applies 2,400 pascals.

Griffith, J. S.↗
NASA NTRS1982

Equipment development for automated assembly of solar modules

Prototype equipment was developed which allows for totally automated assembly in the three major areas of module manufacture: cell stringing, encapsulant layup and cure and edge sealing. The equipment is designed to be used in conjunction with a standard Unimate 2000B industrial robot although the design is adaptable to other transport systems.

Hagerty, J. J.↗
NASA NTRS1981

The solar modulation of the anomalous helium component from 1965 to 1980 and from 1 to 23 A.U.

The modulation of the anomalous He-4 component is investigated both in time and in space from 1 to 23 AU with the spacecraft network of IMP-8, and Pioneers 10 and 11. The times of appearance and disappearance of the anomalous He-4 are determined, and it is found to have a higher sensitivity to modulation both in time and space than cosmic ray protons and helium of equivalent or lower rigidity. The disappearance of the flux due to modulation progressed radially outward over several months suggests that the source lies in the outer heliosphere, probably beyond 25 AU, and possibly out of the ecliptic.

Garcia-Munoz, M.↗