Lower ionosphere at solar minimum.
Lower ionosphere measurements at solar minimum, discussing positive ion density, electron density, solar radiation optical depth, etc
IONOSPHERIC ION DENSITY↗
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Results for “Optical radiation”
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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Information content of photoelectric star images.
Information content of photoelectric star images determined by background radiation, optical aberrations and photon noise, deriving equations for rms error
SIGNAL TO NOISE RATIO↗
Photovoltaic effect in organic polymer-iodine complex
Certain charge transfer complexes formed from organic polymers and iodine generate appreciable voltages at relatively low impedances upon exposure to light. These films show promise in applications requiring chemically and electrically stable films as detectors of optical radiation and as energy converters in photovoltaic cells.
Hermann, A. M.↗
Design, development and experimental verification of atomic beam apparatus Interim scientific report, 15 Jul. 1967 - 30 Apr. 1968
Design, development, and experimental verification of atomic beam apparatus to measure optical radiation produced by collisions of ionized particles with gas molecules
Source record↗
Photomultiplier detection system - Design and applications for artificial meteors.
Artificial meteors optical radiation recording device using photomultiplier tube with increased dynamic range and real time operation
Ayers, W. G.↗
On the nature of the optical flux from extragalactic systems.
Optical radiation from galaxies, discussing starlight, nonthermal flux and radiation from hot gas
Burbidge, G. R.↗
Satellite observations of lightning
Nighttime lightning activity observations by orbiting solar satellite OSO-B, determining thunderstorms positions by optical radiation detection
Ney, E. P.↗
Ion thruster diagnostics using spectral line amplitudes
The optical radiation from the plasma discharge of an electron bombardment mercury ion thrustor was investigated. Using the measured ratio of the Hg I line amplitude at 3655 A to that at 3650 A, a theory incorporating a bimodal electron distribution (Maxwell electrons plus primary electrons) was used to obtain the average electron temperature and primary electron fraction in the thruster ion chamber. The electron temperature ranged from about 1.2 eV to 6.6 eV; whereas the primary electron fraction varied from zero percent to about 5 percent. These values depended upon the discharge voltage and the radial location of the measurement. The percentage of doubly ionized mercury produced in the chamber was also determined as a function of discharge voltage.
Milder, N. L.↗
Experimental investigations of a uranium plasma pertinent to a self-sustaining plasma source
The research is pertinent to the realization of a self-sustained fissioning plasma for applications such as nuclear propulsion, closed cycle MHD power generation using a plasma core reactor, and heat engines such as the nuclear piston engine, as well as the direct conversion of fission energy into optical radiation (nuclear pumped lasers). Diagnostic measurement methods and experimental devices simulating plasma core reactor conditions are discussed. Studies on the following topics are considered: (1) ballistic piston compressor (U-235); (2) high pressure uranium plasma (natural uranium); (3) sliding spark discharge (natural uranium); (4) fission fragment interaction (He-3 and U-235); and (5) nuclear pumped lasers (He-3 and U-235).
Schneider, R. T.↗
Ion thruster diagnostics using spectral line amplitudes.
The optical radiation from the plasma discharge of an electron bombardment mercury ion thruster was investigated. This work extends and refines earlier measurements, correcting certain ambiguities that arose in the analysis of line amplitudes. Using the measured ratio of the Hg I line amplitude at 3655 A to that at 3650 A, a theory incorporating a bimodal electron distribution (Maxwell electrons plus primary electrons) was used to obtain the average electron temperature and primary electron fraction in the thruster ion chamber. The electron temperature ranged from about 1.2 eV to 6.6 eV; whereas the primary electron fraction varied from zero percent to about 5 percent. These values depended upon the discharge voltage and the radial location of the measurement. The percentage of doubly ionized mercury produced in the chamber was also determined as a function of discharge voltage.
Milder, N. L.↗
Beryllium reflected cavity reactor for UF6 critical experiments
Experiments and theoretical studies are being conducted for NASA on critical assemblies with one-meter diam by one-meter long low-density cores surrounded by a thick beryllium reflector. These assemblies make extensive use of existing nuclear propulsion reactor components, facilities, and instrumentation. Due to excessive porosity in the reflector, the initial critical mass was 19 kg U(93.2). Addition of a 17-cm-thick by 89-cm-diam beryllium flux trap in the cavity reduced the critical mass to 7 kg when all the uranium was in the zone just outside the flux trap. A mockup aluminum UF6 container was placed inside the flux trap and fueled with uranium-graphite elements. Fission distributions and reactivity worths of fuel and structural materials are available. These results will be used to guide the design of a prototype plasma core reactor which will test energy removal by optical radiation.
Jarvis, G. A.↗
The transient X-ray source A0620-00 (Nova Monocerotis 1975)
A0620-00 is the first of the so-called X-ray novae to be identified with an optical object. Emission in the ultraviolet, infrared, and radio wavelength regions was observed from this source. From the observed properties of the optical radiation, it is suggested that the source is a recurrent nova.
S. P. Maran↗
Instrumentation for measurements of solar irradiance and atmospheric optical properties
The Active Cavity Radiometer (ACR), an accurate absolute pyrheliometer, has been developed for measurements of total solar irradiance. It has been used to discover a -2.2% error in the International Pyrheliometric Scale and to make measurements in balloon flight experiments yielding a solar constant value of 136.6 (+ or - 0.7) mW/sq cm. New ACRs are being developed to monitor the total output of solar optical radiation in balloon, satellite and space shuttle experiments with long-term absolute uncertainty of + or - 0.1% or less. In a separate program, instrumentation for the measurement of the scattering and extinction of solar radiation by the atmosphere is being constructed to provide data for modeling atmospheric aerosol content. The aerosol models will facilitate computation of radiative transfer effects yielding quantitative net fluxes useful in evaluating the climatological impact of aerosols.
Willson, R. C.↗
Research on plasma core reactors
Experiments and theoretical studies are being conducted for NASA on critical assemblies with one-meter diameter by one-meter long low-density cores surrounded by a thick beryllium reflector. These assemblies make extensive use of existing nuclear propulsion reactor components, facilities, and instrumentation. Due to excessive porosity in the reflector, the initial critical mass was 19 kg U(93.2). Addition of a 17 cm thick by 89 cm diameter beryllium flux trap in the cavity reduced the critical mass to 7 kg when all the uranium was in the zone just outside the flux trap. A mockup aluminum UF6 container was placed inside the flux trap and fueled with uranium-graphite elements. Fission distributions and reactivity worths of fuel and structural materials were measured. Finally, an 85,000 cu cm aluminum canister in the central region was fueled with UF6 gas and fission density distributions determined. These results are to be used to guide the design of a prototype plasma core reactor which will test energy removal by optical radiation.
Jarvis, G. A.↗
Coordinated photometric and spectroscopic observations of strong extragalactic 90 GHz sources
Nearly simultaneous radio and infrared-optical observations were obtained for several extragalactic radio sources which are strong at 90 GHz. The spectral-flux distributions are generally peaked or flat over the radio portion of the spectrum with a steeper, power-law behavior at infrared-optical frequencies. For all sources, the radio and infrared-optical portions of the spectral-flux distributions can be smoothly joined by physically sensible interpolations over the spectral gap, although spectral breaks are required. For many of the sources, this is consistent with a common (synchrotron) origin of the radio, millimeter, and infrared-optical radiation. However, proof, in terms of correlated temporal variations and polarization properties, is still generally lacking.
Odell, S. L.↗
Active cavity radiometer type IV
A new cavity pyrheliometer, the active cavity radiometer type IV (ACR IV), has been developed for the measurement of total solar optical irradiance. Analysis predicts its ability to measure at the solar constant level with 0.1% uncertainty in SI units. In comparison tests ACR IVs have consistently demonstrated 0.3% higher results than the World Radiometric Reference scale. A prototype has been tested, and a flight instrument has been developed and flown in a sounding rocket experiment to determine the solar constant. ACR IV instrumentation is being developed for flight experiments on the Spacelab I and Solar Maximum missions to monitor the total solar output of optical radiation as part of a long-term program to detect variations of climatological significance.
Willson, R. C.↗
Potentials of fissioning plasmas
Successful experiments with the nuclear pumping of lasers have demonstrated that in a gaseous medium the kinetic energy of fission fragments can be converted directly into nonequilibrium optical radiation. This confirms the concept that the fissioning medium in a gas-phase nuclear reactor shows an internal structure such as a plasma in near thermal equilibrium varying up to a state of extreme nonequilibrium. During 20 years of research under NASA support major elements of the fissioning plasma reactor were demonstrated in theory and experiment, culminating in a proof-of-principle reactor test conducted at the Los Alamos Scientific Laboratory. It is concluded that the construction of a gaseous fuel reactor power plant is within the reach of present technology.
Thom, K.↗
The detection of an optical burst coincident with an X-ray burst from MXB 1837 + 05 /Ser X-1/
The detection of a simultaneous optical and X-ray burst from MXB 1837 + 05 (4U 1837 + 04 = Ser X-1) is reported. A similar detection was made earlier from MXB 1735-44. These are the only two burst sources that have been optically observed (simultaneous with X-ray observations) at a high level of sensitivity. Therefore, it may well be that optical bursts commonly accompany X-ray bursts. The relative timing and flux ratio of the optical and X-ray bursts imply that the optical radiation is probably reemission from X-ray-heated matter within 1-2 light seconds of the X-ray source and no more than a few light seconds in extent. This matter may be in an accretion disk around the X-ray source or possibly in the atmosphere of a dwarf companion.
Hackwell, J. A.↗