Maximum number of binary collisions for three relativistic point particles.
Maximum number of binary collisions for three particles with zero range forces in relativistic rescattering singularities studies
Doolen, G.↗
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The effect of suprathermal protons on the physical conditions in Seyfert galaxy nuclei
The physical conditions in a high density hydrogen gas heated and ionized by suprathermal protons were investigated, with application to the gas in the nuclear region of Seyfert galaxies. The gas is assumed optically thick to Lyman and Balmer line radiation. Mechanisms by which the radiation from the gas can balance the heating by the fast protons were investigated, and minimum values for the mass of gas were estimated. Under certain conditions, the suprathermal atoms themselves can cool the ambient gas by rescattering the line radiation into the optically thin region in the wings of the line. This mechanism, called optical reverberation, can enhance the broad component of the hydrogen lines produced by inelastic atomic collisions and yield line widths consistent with those observed in Seyfert and quasar spectra. Also discussed is the possibility of achieving dynamic equilibrium of the ambient gas by balancing the momentum transfer from the suprathermals with gravitational attraction of a massive central source.
Ptak, R.↗
The effect of suprathermal protons on the physical conditions in Seyfert galaxy nuclei
Physical conditions in a high-density hydrogen gas heated and ionized by suprathermal protons are investigated, and the results are applied to the gas in the nuclear region of Seyfert galaxies. The gas is assumed to be optically thick to Lyman and Balmer line radiation. Mechanisms by which the radiation from the gas can balance the heating by the fast protons are investigated, and minimum values for the mass of gas are estimated. Under certain conditions, the suprathermal atoms themselves can cool the ambient gas by rescattering the line radiation into the optically thin region in the wings of the line. This mechanism, optical reverberation, can enhance the broad component of the hydrogen lines produced by inelastic atomic collisions and yield line widths consistent with those observed in Seyfert and quasar spectra. If this mechanism is important, the Lyman decrement can depend strongly on the temperature and density of the ambient hydrogen. The possibility is discussed of achieving dynamic equilibrium of the ambient gas by balancing the momentum transfer from the suprathermals with gravitational attraction of a massive central source.
Ptak, R.↗
Low P sub T hadron-nucleus interactions
The possibility of describing hadron-nucleus (hA) interactions is discussed in terms of a number of independent collisions of the projectile inside the target nucleus. This multiple rescattering may occur on a particle or quark parton level. To investigate the characteristics of hA interactions as a function of antineutrinos advantage is taken of the correlation between the average number antineutrinos of collisions of the projectile inside the nucleus and the number Ng of fast protons ejected from the struck nucleus. The relation antineutrinos vs Ng obtained in antineutrinos was used. For a given target nucleus this allows the selection of interactions occurring at different impact parameters.
Holynski, R.↗
An Improved Neutron Transport Algorithm for Space Radiation
A low-energy neutron transport algorithm for use in space radiation protection is developed. The algorithm is based upon a multigroup analysis of the straight-ahead Boltzmann equation by using a mean value theorem for integrals. This analysis is accomplished by solving a realistic but simplified neutron transport test problem. The test problem is analyzed by using numerical and analytical procedures to obtain an accurate solution within specified error bounds. Results from the test problem are then used for determining mean values associated with rescattering terms that are associated with a multigroup solution of the straight-ahead Boltzmann equation. The algorithm is then coupled to the Langley HZETRN code through the evaporation source term. Evaluation of the neutron fluence generated by the solar particle event of February 23, 1956, for a water and an aluminum-water shield-target configuration is then compared with LAHET and MCNPX Monte Carlo code calculations for the same shield-target configuration. The algorithm developed showed a great improvement in results over the unmodified HZETRN solution. In addition, a two-directional solution of the evaporation source showed even further improvement of the fluence near the front of the water target where diffusion from the front surface is important.
Heinbockel, John H.↗