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Results for “ELECTRON DENSITY”

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 253 records · Page 14
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NASA NTRS1976

Line-of-sight electron density gradients as deduced from an empirical ionospheric model

A topside ionospheric model (Bent Ionospheric Model) was developed for an accurate prediction of integrated total electron content (TEC), from a global data acquired for the years 1962 to 1969. In this paper the effects of line-of-sight electron density gradients on ground to satellite measurements are discussed. The results of analyses show that in the presence of increasing density gradients, deduced values of vertical electron content or slab thicknesses will be too large, while for decreasing gradients these values will be smaller than they should be.

Nesterczuk, G.↗
NASA NTRS1972

Quasi-linear theory of electron density and temperature fluctuations with application to MHD generators and MPD arc thrusters

Fluctuations in electron density and temperature coupled through Ohm's law are studied for an ionizable medium. The nonlinear effects are considered in the limit of a third order quasi-linear treatment. Equations are derived for the amplitude of the fluctuation. Conditions under which a steady state can exist in the presence of the fluctuation are examined and effective transport properties are determined. A comparison is made to previously considered second order theory. The effect of third order terms indicates the possibility of fluctuations existing in regions predicted stable by previous analysis.

Smith, M.↗
NASA NTRS1972

Quasi-linear theory of electron density and temperature fluctuations with application to MHD generators and MPD arc thrusters.

Fluctuations in electron density and temperature coupled through Ohm's law are studied for an ionizable medium. The nonlinear effects are considered in the limit of a third order quasi-linear treatment. Equations are derived for the amplitude of the fluctuation. Conditions under which a steady state can exist in the presence of the fluctuation are examined and effective transport properties are determined. A comparison is made to previously considered second order theory. The effect of third order terms indicates the possibility of fluctuations existing in regions predicted stable by previous analysis.

Smith, J. M.↗
NASA NTRS1977

Development of far infrared attenuation to measure electron densities in cw pin discharge lasers

A two beam attenuation technique was devised to measure electron densities 10 to the 9th power to 10 to the 11th power cm/3 resolved to 1 cm, in a near atmospheric COFFEE laser discharge, using 496 micrometer and 1,220 micrometer radiations from CH3F, optically pumped by a CO2 laser. A far infrared generator was developed which was suitable except for a periodic intensity variation in FIR output deriving from frequency variation of the pump radiation.

Babcock, R. V.↗
NASA NTRS1978

Rocket observations of electron-density irregularities in the equatorial ionosphere below 200 km

Nike Apache rockets carring instrumentation to measure electron density and its fine structure in the equatorial ionosphere were launched from Chilca, Peru in May and June 1975. The fine structure experiment and the data reduction system are described. Results obtained from this system are presented and compared with those obtained by VHF radar and from other rocket studies. A description of the equatorial ionosphere and its features is also presented.

Klaus, D. E.↗
NASA NTRS1981

Electron densities for six planetary nebulae and HM SGE derived from the C 3 lambda 1907/1909 ratio

Electron densities for IC 418, NGC 6572, IC 1297, NGC 3242, NGC 6818, NGC 3211, and HM Sge derived from high dispersion IUE C III spectrograms are consistently higher than those derived from either surface brightness measurements of forbidden line intensity ratios in the visible. The nebulae were selected for a range of excitation classes from 3 to 9. Line splitting due to expansion velocities is observed for three objects. The great width of the lambda 1909 C III line in HM Sge suggests large expansion velocities.

Source record↗
NASA NTRS1990

New options for IRI electron density in the middle ionosphere

This paper reviews the present International Reference Ionosphere (IRI) model of electron density in the middle ionosphere and explores two new options for future editions of IRI. The first of these options is a better description of the bottomside thickness parameters, and the second is an analytical representation from E- to F2-peak using LAY-functions. For this analytical representation a table of standard parameters and constraints for the four LAY-functions recommended for IRI have been established.

Bilitza, Dieter↗
NASA NTRS1992

Sites of fine-scale electron density turbulence in the interstellar medium

Observations of radio-wave scattering effects probe interstellar electron-density turbulence. But with limited use of complementary data sets only broad conclusions have been obtained. The locations of this turbulence are unknown (phases, objects, etc.), as is the mechanism for its production, although it could play a role in various galactic processes. The IRAS data set was used to search for correlations between scattering and structures traced by infrared emitting dust. The existent HI (21-cm line emission), and 408-MHz radio-continuum all-sky surveys were used to search for correlations between scattering and structures traced by these emissions. Only lines of sight outside the galactic plane were considered (to better delimit the structures which might be causing scattering). No correlation is apparent between 21-cm line emission, or infrared continuum emission and interstellar scattering. However, a correlation exists between the scattering toward extragalactic radio sources and 408-MHz continuum emission.

Simonetti, John H.↗