Particles and fields
Particles and fields research in 1967, including solar wind interactions and cosmic ray data
Kavanagh, L. D., Jr.↗
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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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Solar cosmic rays
Solar cosmic ray data, discussing multicharged nuclei relative abundances in photosphere and propagation models
Fichtel, C. E.↗
Galactic cosmic ray heavy primary secondary doses
Results of a calculation which estimates the heavy primary secondary doses from cosmic ray interaction data are reported. The incident galactic cosmic ray heavy primary spectrum is represented as the sum of helium, nitrogen, magnesium, and iron components. The incident iron nuclei are allowed to fragment into lesser Z secondaries, which are assumed to travel in the same direction and start with the same energy per nucleon as the interacting primary. The total emergent particle energy spectra and dose are then presented for the galactic heavy primary spectrum incident on aluminum and tissue slabs. The importance of the fragmentation parameters assumed is also evaluated. The total dose from the heavy primaries and their secondaries is found to be reduced by only a factor of two in 20 g/sq cm of shielding.
Wilkinson, M. C.↗
Nuclear reactions induced by high-energy alpha particles
Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.
Shen, B. S. P.↗
The variation of solar proton energy spectra size distribution with heliolongitude
A statistical study of the initial phases of 185 solar particle events was carried out using the data from cosmic ray experiments on IMP 4 and IMP 5. Special emphasis was placed on the identification of the associated solar flare, as the parent flare can be determined for 68% of the events. It appears probable that most of the unidentified increases occur on the non-visible disc of the sun. The existence of a 'preferred-connection' longitude between 20 W and 80 W was established by examining the heliolongitude of all the flare associated events. It is demonstrated that the energy spectra determined at the time of maximum particle in the 20 to 80 MeV or 4 to 20 Mev interval range give results identical to that obtained by the 'distance-travelled' method.
Vanhollebeke, M. A. I.↗
Hyperbolic cosmic dust - Its origin and its astrophysical significance
The heliocentric radial distribution of the flux of hyperbolic cosmic dust particles, as measured by the Pioneer 8 and 9 spacecraft, is closely related to the radial variation of the spatial density of source or parent meteoroids. Within the limits of the experimental and theoretical uncertainties the spatial density of parent meteoroids, as deduced from the hyperbolic cosmic dust data, is found to be increasing with increasing heliocentric distance in the neighborhood of one AU. Other recent experimental evidence confirms this result. The new results also suggest that the ratio of the areal density of submicron-sized craters to the areal density of millimeter-sized craters will be less on the north-south faces of lunar rocks than on the east-west faces of the same rocks. The change in ratio is not as large as previously thought. It is noted that the solar system is not presently contributing significant amounts of dust to the interstellar medium though it may once have done so.
Zook, H. A.↗
A study of the effects of Forbush decreases and the 11-year variation of cosmic rays out to approximately 16 AU
In this study the onset of the new solar modulation cycle in late 1977 has been observed out to 16 AU. 27-day average cosmic-ray data (E greater than 60 MeV) from Pioneers 10, 11 and IMP 8 for the period for 1973-1978, normalized to the ground-based neutron monitor rates, have been used. Observations indicate that the long-term modulation effects propagate outward radially at 200-300 Km/sec. Forbush decreases, in contrast, are local phenomena and the associated time delays between their occurrence at earth and out to a few AU are much shorter. The data yield a radial gradient of 2-3% per AU.
Lockwood, J. A.↗
Interstellar photoelectric absorption cross sections, 0.03-10 keV
An effective absorption cross section per hydrogen atom has been calculated as a function of energy in the 0.03-10 keV range using the most recent atomic cross section and cosmic abundance data. Coefficients of a piecewise polynomial fit to the numerical results are given to allow convenient application in automated calculations.
Morrison, R.↗
A 50 day periodicity in the cosmic ray anisotropy
A modulation of the anisotropy of relativistic interplanetary particles with a period of approximately 50 days is discussed. Even though it is not unusual for cosmic ray data to reflect the solar rotation frequency and its harmonics with periods of 25/n days (n being 1, 2, 3, . . .), it is not known how a periodicity of 50 days, which would be a subharmonic, is generated. Since the Cerenkov counter responds to all kinds of relativistic particles, it does not identify the particles that cause the 50 day east-west modulation. Jovian electrons are considered unlikely in that they are most abundant near their source, whereas the modulation has never been reported for ground-based neutron monitors. It is pointed out that since the Cerenkov threshold is somewhat lower than typical neutron monitor cutoffs, it is conceivable that the modulation affects nucleons just in this energy gap. It is also thought that there might be a uniformly distributed component of interplanetary electrons which undergo this peculiar modulation.
Fillius, W.↗
Cosmic ray intensity variations observed at Matsushiro (220 M.W.E. in depth)
Cosmic ray data from Matsushiro underground station were analyzed for four years (1981 to 84). It is found that a marked semi-annual intensity variation has been observed in this period. Solar diurnal and semi-diurnal variations have also been observed. After correcting for the spurious sidereal diurnal variation arising from the anisotropy responsible for the solar semi-diurnal variation (Nagashima et al., 1983), it is found that the corrected sidereal diurnal variation is consistent with those so far reported.
Yasue, S.↗
Dimensions of the solar wind cavity and of the region of interplanetary cosmic ray modulation
The problem of determining effective dimensions of the region of global galactic cosmic ray modulation from the data on 11 year cosmic ray variations and the data on the parameters of the solar activity and the solar wind is discussed.
Dorman, I. V.↗
QCD-motivated description of very high energy particle interactions
Cross sections for the production of secondaries with large transverse momentum can become comparable to the total cross section in the TeV energy range. It is argued that the onset of this effect is observed at sub TeV energies via an increase of the rapidity distribution near y = 0, an increase of p sub T with energy and, most directly, via a correlation between p sub T and multiplicity. If indeed scaling violations are associated with the hard scattering of partons, then scaling violations are largely confined to the central region and have little effect on cosmic ray data which are sensitive to the forward fragmentation region.
Gaisser, T. K.↗
The structure of EAS at E 0.1 EeV
The ratio of extensive air showers (EAS) total shower energy in the electromagnetic channel (E em) to the size of the shower at maximum development (N max) from a direct measurement of shower longitudinal development using the air fluorescence technique was calculated. The values are not inconsistent with values based upon track length integrals of the Gaisser-Hillas formula for shower development or the known relation between shower energy and size at maximum for pure electromagnetic cascades. Using Linsley's estimates for undetected shower energy based on an analysis of a wide variety of cosmic ray data, the following relation for total shower energy E vs N max is obtained. The Gaisser Hillas implied undetected shower energy fractions.
Baltrusaitis, R. M.↗
A new world survey expression for cosmic ray vertical intensity vs. depth in standard rock
The cosmic ray data on vertical intensity versus depth below 10 to the 5th power g sq cm is fitted to a 5 parameter empirical formula to give an analytical expression for interpretation of muon fluxes in underground measurements. This expression updates earlier published results and complements the more precise curves obtained by numerical integration or Monte Carlo techniques in which the fit is made to an energy spectrum at the top of the atmosphere. The expression is valid in the transitional region where neutrino induced muons begin to be important, as well as at great depths where this component becomes dominant.
Crouch, M.↗
Simulation and study of small numbers of random events
Random events were simulated by computer and subjected to various statistical methods to extract important parameters. Various forms of curve fitting were explored, such as least squares, least distance from a line, maximum likelihood. Problems considered were dead time, exponential decay, and spectrum extraction from cosmic ray data using binned data and data from individual events. Computer programs, mostly of an iterative nature, were developed to do these simulations and extractions and are partially listed as appendices. The mathematical basis for the compuer programs is given.
Shelton, R. D.↗
Galactic antiprotons from photinos
Stable photinos, the photino being the supersymmetry partner of the photon, can explain both the 'missing mass' in galactic halos and the cosmic-ray antiproton spectrum up to the highest energies observed so far. This requires a photino mass around 15 GeV; significantly higher masses are cosmologically disfavored. As a consequence, the observed cosmic-ray antiproton-to-proton ratio is predicted to decrease abruptly just above the measured energy range, at E = m(x). If observed, this striking effect would strongly support the hypothesis that photinos make up the missing matter in the galaxy and also lead to a measurement of the photino mass from cosmic-ray data.
Stecker, F. W.↗
Meson multiplicity versus energy in relativistic nucleus-nucleus collisions
A systematic study of meson multiplicity as a function of energy at energies up to 100 GeV/u in nucleus-nucleus collisions has been made, using cosmic-ray data in nuclear emulsion. The data are consistent with simple nucleon-nucleon superposition models. Multiplicity per interacting nucleon in AA collisions does not appear to differ significantly from pp collisions.
Atwater, T. W.↗
Cosmic-ray antiprotons, positrons, and gamma rays from halo dark matter annihilation
The subject of cosmic ray antiproton production is reexamined by considering other choices for the nature of the Majorana fermion chi other than the photino considered in a previous article. The calculations are extended to include cosmic-ray positrons and cosmic gamma rays as annihilation products. Taking chi to be a generic higgsino or simply a heavy Majorana neutrino with standard couplings to the Z-zero boson allows the previous interpretation of the cosmic antiproton data to be maintained. In this case also, the annihilation cross section can be calculated independently of unknown particle physics parameters. Whereas the relic density of photinos with the choice of parameters in the previous paper turned out to be only a few percent of the closure density, the corresponding value for Omega in the generic higgsino or Majorana case is about 0.2, in excellent agreement with the value associated with galaxies and one which is sufficient to give the halo mass.
Rudaz, S.↗