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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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Calculation of diffusion and drift velocities in nightime F region, and measurements of ion density in D-region of ionosphere
First-order correction to Hoult theory for measuring ion density in D region, especially those involving heat transfer and compressibility
Weak shock effects and chemistry of lower D region, and blunt supersonic probe theory and first order corrections
Comprehensive energy density studies provide an important measure of the participation of various sources in energization processes and have been relatively rare in the literature. We present a statistical study of the energy density of the near-Earth magnetotail major ions (H(+), O(+), He(++), He(+)) during substorm expansion phase and discuss its implications for the solar wind/magnetosphere/ionosphere coupling. Our aim is to examine the relation between auroral activity and the particle energization during substorms through the correlation between the AE indices and the energy density of the major magnetospheric ions. The data we used here were collected by the charge-energy-mass (CHEM) spectrometer on board the Active Magnetospheric Particle Trace Explorer (AMPTE)/Charge Composition Explorer (CCE) satellite in the near-equatorial nightside magnetosphere, at geocentric distances approximately 7 to 9 R(sub E). CHEM provided the opportunity to conduct the first statistical study of energy density in the near-Earth magnetotail with multispecies particle data extending into the higher energy range (greater than or equal to 20 keV/E). the use of 1-min AE indices in this study should be emphasized, as the use (in previous statistical studies) of the (3-hour) Kp index or of long-time averages of AE indices essentially smoothed out all the information on substorms. Most distinct feature of our study is the excellent correlation of O(+) energy density with the AE index, in contrast with the remarkably poor He(++) energy density - AE index correlation. Furthermore, we examined the relation of the ion energy density to the electrojet activity during substorm growth phase. The O(+) energy density is strongly correlated with the pre-onset AU index, that is the eastward electrojet intensity, which represents the growth phase current system. Our investigation shows that the near-Earth magnetotail is increasingly fed with energetic ionospheric ions during periods of enhanced dissipation of auroral currents. The participation of the ionosphere in the substorm energization processes seems to be closely, although not solely, associated with the solar wind/magnetosphere coupling. That is, the ionosphere influences actively the substorm energization processes by responding to the increased solar wind/magnetosphere coupling as well as to the unloading dissipation of stored energy, with the increased feeding of new material into the magnetosphere.
It is pointed out that ion mass spectrometers operating in the keV range have recently begun to provide a new class of information on magnetospheric processes. One of the principal motivations for the development of energetic ion mass spectrometers has been to investigate the origins of the hot plasma populations of the magnetosphere. Peterson et al. (1981) were able to estimate the fractional ion density of ionospheric origin in five intervals by intercomparing the He(++) and H(+) spectra and assuming the excess low-energy H(+) ions were from the ionosphere. They obtained values in the range from 0.1 to 0.65. The present investigation is concerned with an expansion of the previous study. A substantially larger data base is utilized, and a different set of assumptions is considered to infer the relative fractions of solar and ionospheric H(+) and to look for systematic changes in the relative source strengths with magnetic activity.
An international conference on high-latitude ionospheric modeling produced 27 papers in the areas of ionospheric mapping, electron density and distribution, ion density and distribution, ionospheric storems, ionospheric composition, and ionospheric sounding techniques. Upgrades to the International Reference Ionosphere (IRI) model were proposed in several papers.
Theoretical models have been used to investigate the effects of artificially injected H2 gas on plasma densities in the ionospheric F region and the overlying protonosphere. Owing to large reaction rates between H2 and ionospheric O(+) ions, plasma densities in both daytime and nighttime ionospheres can be greatly reduced by modest amounts of released H2 gas. One hundred kg of H2 released at 300-km altitude reduces local O(+) densities by more than three orders of magnitude and produces about a 5% depression in H(+) densities in the overlying protonosphere. These results suggest that it should be possible to conduct controlled chemical-modification experiments for investigation of many outstanding ionospheric and magnetospheric problems.
Helium and hydrogen ions, used to calculate atmospheric temperature, ion mass and ion concentration as functions of altitude
Lower ionosphere measurements at solar minimum, discussing positive ion density, electron density, solar radiation optical depth, etc
The response of the ionospheric E-region to solar-geomagnetic storms can be characterized using observations of infrared 4.3 micrometers emission. In particular, we utilize nighttime TIMED/SABER measurements of broadband 4.3 micrometers limb emission and derive a new data product, the NO+(v) volume emission rate, which is our primary observation-based quantity for developing an empirical storm-time correction the IRI E-region electron density. In this paper we describe our E-region proxy and outline our strategy for developing the empirical storm model. In our initial studies, we analyzed a six day storm period during the Halloween 2003 event. The results of this analysis are promising and suggest that the ap-index is a viable candidate to use as a magnetic driver for our model.
Ariel satellite - electron density, temperature, ion distribution and concentration in ionosphere
Brief discussion of the concentration of helium ions in the upper atmosphere, emphasizing its dependence on temperature
Experimental evidence for a low ion-transition altitude in the upper nighttime ionosphere
Atmospheric ionic composition determination, electron temperatures, and solar activity experiments from explorer viii satellite
Nighttime F layer maintained by hydrogen ions providing source of oxygen ions through charge exchange or by upward drift of ionization
Ionic composition above F layer maximum from Ariel I satellite ion mass spectrometer
Ion-molecule reaction rates and recombination coefficients from mass spectrometric ionospheric data
Smith subprotonospheric whistlers and digital computation of ion effects on whistler-mode ray tracing