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Effects of columnar recombination on conductivities of nuclear seeded plasmas
Nonlinear effects of recombination and collective diffusion associated with nuclear seeded plasmas using helium isotopes in gas cooled reactors
The abundances of the elements.
For the immediate cosmic environs, there are three traditional sources of element abundance data, including chondritic meteorites, the solar atmosphere, and a certain type of average of stars near the sun. Cosmic ray material, or at least the particles that were accelerated to very high energies, includes contributions from great distances in the Galaxy, and perhaps from outside the Milky Way system itself. Problems in the determination of solar system abundances are discussed together with some factors affecting the profiles of spectral lines, the abundances of some elements in the solar atmosphere, young stars and the interstellar medium, the helium to hydrogen ratio, the helium isotopes, and abundances of light elements in the Galaxy and in neighboring galaxies.
Deuterium and tritium from solar flares at approximately 10 MeV per nucleon
It is indicated that the observations with the high-resolution solid-state charged-particle telescopes of the IMP-5 and IMP-6 earth satellites have resolved all the hydrogen and helium isotopes of solar-flare origin in groups of solar flares during the period from September, 1969, through November, 1972. The values obtained for the average isotope ratios are given and are compared with previous values. It is concluded that the observed high yields of H(2), H(3) and He(3) can be explained only by high-energy nuclear interactions and that an acceleration process must have taken place in the chromosphere at that time.
Solar energetic particle event with He-3/He-4 greater than 1
An unusual solar event involving the detection of a He-3/He-4 ratio of about 1.5 was observed with the aid of the cosmic-ray telescopes of OGO-V on May 28, 1969. A theory dealing with the production of H-2, H-3, and He-3 in solar events is considered together with the conditions which would have to be satisfied in order to explain the observed very high helium isotope ratio in terms of the theory.
Critical point parameters of helium
Calculations of the critical point parameters of the helium isotopes using integral equation closures for the pair distribution function are reported for two pair potentials.
Nuclear-pumped gas lasers
Laser pumping incorporates use of volumetric helium isotope reaction. Reaction deposits energy nearly uniformly throughout laser volume. Method improves efficiency of system as compared with conventional coating method.
Cosmic-ray-produced neon and helium in the summit lavas of Maui
The identification of cosmic-ray-produced Ne-21c in addition to He-3c, components attributed to cosmic ray-induced spallation reactions, are reported in gases extracted by fusion of olivines and clinopyroxenes after vacuum-crushing. The observed (He-3/Ne-21)c ratios and the ratio of Ne-21c in olivine to that in clinopyroxene are consistent with an in situ origin of He-3c and Ne-21c by cosmic-ray spallation reactions. These components could be important for interpreting helium isotopic data in terrestrial reservoirs. Geophysical applications could include determinations of erosion rates and exposure histories of terrestrial rocks.
Magnetism of Carbonados
Carbonados are porous polycrystalline (with crystal sizes up to 100 micrometer) diamonds. Carbonado is found only in alluvial deposits in Bahia, Brazil and in the Central African Republic (CAR). Alluvial deposit host is 1.5 Ga while the carbonados are between 2.6 - 3.8 Ga. The process of fusing the carbonado microcrystals together is not fully understood, partly due to fact that the origin of these carbonado, is not known. Several modes of origins are proposed for carbonado. First, a crustal origin. Carbonados have a light carbon and helium isotopic signature. They contain an enrichment of the rare-earth elements (REE). Carbonados have tightly trapped atmospheric noble gases and contain an evidence of high He content despite the carbonado expected depletion of He at mantle temperatures. Carbonados have high porosity incompatible with high pressure mantle conditions. Second, a mantle origin is proposed based on similar REE pattern to kimberlites. The presence of nitrogen platelet (by IR spectra) indicates high temperature origin and syngenetic inclusions of rutile, ilmenite, and magnetite indicates high pressure and high temperature conditions consistent with mantle origin as well. Third, it is proposed that carbonado diamonds are a result of early impacts into crustal rocks. This is indicated by the rare and controversial occurrence of high pressure diamond polymorph, londsdaleite, frequently found in diamonds from meteorite impact sites, and by observation of planar deformation features, possibly indicating shock events. Finally, it is suggested that carbonados have an extraterrestrial origin, as indicated by a long term annealing based on observation of a zero-phonon line, attributed to paired nitrogen atoms in association with a vacancy.
Description of Light Ion Production Cross Sections and Fluxes on the Mars Surface using the QMSFRG Model
The atmosphere of Mars significantly attenuates the heavy ion component of the primary galactic cosmic rays (GCR), however increases the fluence of secondary light ions (neutrons, and hydrogen and helium isotopes) because of particle production processes. We describe results of the quantum multiple scattering fragmentation (QMSFRG) model for the production of light nuclei through the distinct mechanisms of nuclear abrasion and ablation, coalescence, and cluster knockout. The QMSFRG model is shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections. We use the QMSFRG model and the space radiation transport code, HZETRN to make predictions of the light particle environment on the Martian surface at solar minimum and maximum. The radiation assessment detector (RAD) experiment will be launched in 2009 as part of the Mars Science Laboratory (MSL). We make predictions of the expected results for time dependent count-rates to be observed by RAD experiment. Finally, we consider sensitivity assessments of the impact of the Martian atmospheric composition on particle fluxes at the surface.
Study of isotopic composition of helium in the fine fraction of Luna 16 lunar surface material
The content of He isotopes is measured in two samples of the lunar surface material returned by the Luna 16 automatic station. Both samples consist of a fine fraction of lunar surface material and were samples from zone A (sample 3-2k) and from zone V (sample 9-1r). The value of He4/He3 and the concentration of the He isotopes are identical for both samples, within the limits of experimental error.
The isotopic composition of helium in the cosmic radiation above 11 gigavolts
The He-3/He-4 abundance ratio above 11 GV has been measured with a balloon-borne experiment that employs the geomagnetic method of isotope separation near earth's equator. Above a kinetic energy of approximately 6 GeV per nucleon, the He-3/He-4 ratio is measured to be 0.24 + or - 0.05 under the assumption that the helium spectrum at earth is a power law in rigidity of the form R to the -2.65th. The implied interstellar mean escape pathlength of about 15 g per sq cm, with this assumption, is considerably greater than values determined from observations of heavier elements. Propagation models more complex than the standard simple leaky box would be required to simultaneously understand the propagation of both the lighter and heavier components of cosmic rays.
The ratios of carbon and non-radiogenic helium and argon isotopes in the mantle and crustal rocks
The studies of the relations of carbon and primary isotopes of noble gases were carried out on the natural gases and on the mantle rocks from the mantle M-type sources, which represent the degassed mantle reservoir (MORB's). These works has the aim of estimation of the values of the C/3He ratios in the deep mantle fluids to determine the flux of the mantle CO2 on the basis of known flux of primary mantle 3He. It was found, that in the natural gases the values of the C/3He ratios fall into the range from 1 times E plus 6 to 1 times E plus 15, and in the fluids of MORB's are constant near 2 times E plus 9. We have studied the mantle rocks from the relatively undergassed mantle P minus type sources: continental; Baikal Rift (Siberia), Mongolia, Catalonia (Spain), Pannonia Depression (central Europe) and ocean; Spietzbergen isl., Hawaii isl., Canarian isl. It ws found, that in mantle xenolites and the host alkaline basalts from the continental rifts and ocean islands, the values of the C/3He ratios fall into the range from E plus 11 to E plus 15 (and this result needed to be explained; the higher carbon to helium ratios is relatively undergassed mantle reservoir compared with the degassed one, requires whether hilly compatibility of helium compared with carbon, whether additional flux of 3He to the degassed mantle reservoir). From the other hand it was found that in the mantle rocks from the sources of P minus and M minus types, continental carbonatites, the values of the C/36Ar ratios are constant in the range from E plus 9 to E plus 10, the close values have the MORB's also.
Helium and neon isotopes in stratospheric particles
He and Ne isotope ratios were determined for 16 interplanetary dust particles (IDPs) collected in the stratosphere. The observed He concentration varied greatly from particle to particle, with the highest values approaching those found for lunar surface fines and some gas-rich meteorites. The average Ne-20/Ne-22 ratio was 12.0 + or - 0.5. The data suggest that the observed IDPs could have entered the atmosphere at relatively low velocities, and hence may be primarily of asteroidal rather than cometary origin.
On the origins of trapped helium, neon and argon isotopic variations in meteorites. I - Gas-rich meteorites, lunar soil and breccia. II - Carbonaceous meteorites.
Data are presented from stepwise heating experiments and total extractions on five meteorites: Kapoeta, Fayetteville, Holman Island, Cee Vee, and Pultusk. These data reveal the presence of four isotopically distinct trapped neon components. A comparison of trapped neon with trapped helium and argon in bulk analyses indicates the existence of correlated helium, neon and argon isotopic structures. Component B is attributed primarily to direct implantation of rare gas ions by the present day solar wind. Component C is identified with directly implanted low energy (1-10 Mev/n) solar flare rare gases. Component D is associated with rare gas ions implanted in meteoritic material by the primitive, pre-main sequence, solar wind. A fourth component, observed only in Kapoeta and the lunar fines and breccia, is tentatively attributed to parent body 'atmospheric' ions implanted in surface material by a solar wind induced electric field.
Isotopic composition of primordial helium in carbonaceous chondrites
Carbonaceous chondrites primordial He and Ne isotopes variations
Measurement and interpretation of the isotopic composition of hydrogen and helium cosmic-ray nuclei below 75 Mev/nucleon.
Hydrogen and helium cosmic ray nuclei isotopic composition measured to clarify abundance ratios energy dependence below 75 Mev/nucleon
Solar flare accelerated isotopes of hydrogen and helium
Measurements of solar flare hydrogen, deuterium, tritium, helium-3, and helium-4 in the energy range approximately 10 to 50 MeV per nucleon obtained with instrumentation on the IMP-4 and IMP-5 satellites are reported and studies based on these results which place several constraints on theories of solar flare particle acceleration are discussed. A brief review of previous work and the difficulties in studying the rare isotopes of hydrogen and helium is also included. Particular emphasis is placed on the fact that the information to be obtained from the solar flare products of high energy interactions is not available through either solar wind observations where both the acceleration mechanism and the coronal source of the nuclear species are different, or optical measurements of solar active regions.