Temperature relaxation in a fully ionized plasma.
Anisotropic ion or electron temperature relaxation times to isotropy and to equilibrium calculated, using plasma kinetic equation including dynamic shielding
PLASMA TEMPERATURE↗
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Preliminary investigation of feasibility of weaving triaxial fabrics Final report
Preliminary investigations to determine stability, isotropy, and feasibility of weaving triaxial fabrics
Dow, N. F.↗
Molecular orientation and mechanical anisotropy in polyethylene, polypropylene, and poly/ethylene terephthalate/ films
Molecular orientation and mechanical isotropy in polyethylene, polypropylene, and polyethylene terephthalate films
Price, H. L.↗
Instability of transverse waves in a relativistic plasma.
Transverse waves instability in relativistic plasma, noting condition of isotropy and existence of electromagnetic waves
Lerche, I.↗
Techniques in balloon X-ray astronomy.
Since the first balloon observation of the Crab Nebula balloon data have provided much information on the positions, spectra, time variability and pulsed nature of localized sources, and on the spectrum and isotropy of diffuse galactic and universal components. Measurements are limited to energies above about 20 keV by atmospheric attenuation at 2 to 3 g/sq cm depth and to below several hundred keV by detector sensitivity. Detectors usually consist of large-area Na I or Cs I scintillation counters with anticoincidence collimators for rejection of charged particles and scattered X-rays. Proportional counters are occasionally used at lower energies and solid-state detectors are used where extreme energy resolution is important. The instruments require a pointing capability on the order of 1.0 to 0.1 deg, depending on the collimator aperture. Digital data is either recorded on board or telemetered using a PCM technique.
Peterson, L. E.↗
Statistical turbulence theory and turbulence phenomenology
The application of deductive turbulence theory for validity determination of turbulence phenomenology at the level of second-order, single-point moments is considered. Particular emphasis is placed on the phenomenological formula relating the dissipation to the turbulence energy and the Rotta-type formula for the return to isotropy. Methods which deal directly with most or all the scales of motion explicitly are reviewed briefly. The statistical theory of turbulence is presented as an expansion about randomness. Two concepts are involved: (1) a modeling of the turbulence as nearly multipoint Gaussian, and (2) a simultaneous introduction of a generalized eddy viscosity operator.
Herring, J. R.↗
The origin of the diffuse background gamma-radiation
Recent observations have now provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV. There is some evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation have been observed which provide evidence for its origin in nuclear processes in the early stages of the big-band cosmology and tie in these processes with galaxy fromation theory. A crucial test of the theory may lie in future observations of the background radiation in the 100 MeV to 100 GeV energy range which may be made with large orbiting spark-chamber satellite detectors. A discussion of the theoretical interpretations of present data, their connection with baryon symmetric cosmology and galaxy formation theory, and the need for future observations are given.
Stecker, F. W.↗
Calculated photoelectron pitch angle and energy spectra
Calculations of the steady-state photoelectron energy and angular distribution in the altitude region between 120 and 1000 km are presented. The distribution is found to be isotropic at all altitudes below 250 km, while above this altitude anisotropies in both pitch angle and energy are found. The isotropy found in the angular distribution below 250 km implies that photoelectron transport below 250 km is insignificant, while the angular anisotropy found above this altitude implies a net photoelectron current in the upward direction. The energy anisotropy above 500 km arises from the selective backscattering of the low energy photoelectron population of the upward flux component by Coulomb collisions with the ambient ions. The total photoelectron flux attains its maximum value between about 40 and 70 km above the altitude at which the photoelectron production rate is maximum. The displacement of the maximum of the equilibrium flux is attributed to an increasing (with altitude) photoelectron lifetime. Photoelectrons at altitudes above that where the flux is maximum are on the average more energetic than those below that altitude.
Mantas, G. P.↗
Computation of turbulent flows
All of the work deals with a model that incorporates dynamical equations for the mean velocity field, for all components of the Reynolds stress tensor, and for the 'isotropic dissipation'. The trace of the Reynolds stress tensor provides a velocity scale for the turbulence. For completeness, a turbulence length or time scale is also needed; many workers impose the length scales, but in a generalized model it must be evolved by the turbulence itself. In order, the following special classes of flows are considered: (1) decay of isotropic turbulence, (2) return to isotropy in homogeneous turbulence without strain, (3) homogeneous turbulence with strain, and (4) inhomogeneous turbulence with strain and turbulent transport.
Reynolds, W. C.↗
Propagation of cosmic rays in the galaxy
The characteristics of a model for analyzing the propagation of cosmic rays are discussed. The requirements for analyzing the relevant observational data on cosmic rays are defines as: (1) the chemical and isotopic composition of cosmic rays as a function of energy, (2) the flux and energy spectrum of the individual nucleonic components, (3) the flux and energy spectrum of the electronic component, (4) the cosmic ray prehistory, and (5) the degree of isotropy in their arrival directions as a function of energy. It is stated that the model which has been able to bring to pass the greatest measure of success is the galactic confinement model.
Daniel, R. R.↗
Broadband noise generated by turbulent inflow to rotor or stator blades in an annular duct
The Green's function relating the radiated pressure field to the fluctuating forces on rotor or stator blades is developed in the presence of dissipation due to turbulent velocity fluctuations and sound speed fluctuations. The resonances in the output power spectrum which would occur at the cut-off frequencies in the absence of dissipation should be removed and smeared out by the incorporation of dissipation. Wave number dependence is developed for an effective eddy viscosity due to the aforementioned fluctuations in the background medium. The space-time correlation function for blade-normal velocity fluctuations on a single or on two different blades is developed in terms of the velocity correlation tensor for the inflow under the assumptions of isotropy and (Taylor) frozen behavior. The correlation function is then simplified under certain approximations and the behavior of the blade-force correlation function is inferred.
Lnae, F.↗
Electron precipitation in the post midnight sector of the auroral zones
Comprehensive measurements of the angular distributions and energy spectra of electron intensities with electrostatic analyzer arrays on board the low-altitude satellite Injun 5 are reported. These are for the post-midnight sector of the auroral zones during the high-intensity events accompanying magnetic substorms. Precipitation features on closed terrestrial field lines well equatorward of the trapping boundary for energetic electrons with E greater than 45 keV were examined. No evidences of maxima in the differential energy spectra or of strongly field-aligned currents which are indicative of quasi-static electric fields aligned parallel to the geomagnetic field were found. Precipitation of low-energy electron intensities fluctuated on time scales greater than 2 seconds as viewed at the satellite position. This precipitation was characterized by isotropy for all pitch angles outside the atmospheric backscatter cone.
Frank, L. A.↗
The origin of the diffuse background gamma radiation
Recent observations provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV, and evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation were observed which provide evidence for its origin in nuclear processes in the early stages of big-bang cosmology, and connect these processes with the galaxy formation theory. A test of the theory is in future observations of the background radiation in the 100 MeK to 100 GeV energy range which are made with large orbiting spark-chamber satellite detectors. The theoretical interpretations of present data, their connection with baryon-symmetric cosmology and galaxy formation theory, and the need for future observations are discussed.
Stecker, F. W.↗
Calculated photoelectron pitch angle and energy spectra
Calculations of the steady-state photoelectron energy and angular distribution in the altitude region between 120 and 1000 km are presented. The distribution is found to be isotropic at all altitudes below 250 km, while above this altitude anisotropies in both pitch angle and energy are found. The isotropy found in the angular distribution below 250 km implies that photoelectron transport below 250 km is insignificant, while the angular anisotropy found above this altitude implies a net photoelectron current in the upward direction.
Mantas, G. P.↗
Neutral hydrogen flux measured at 100- to 200-km altitude in an electron aurora
Neutral hydrogen fluxes were measured at altitudes of 120-200 km by a rocket payload that also measured electron and proton fluxes and vector magnetic fields. An intense electron arc was crossed, while an upper limit to the flux of 0.5- to 20-keV protons was 1,000,000 per sq cm s sr keV. A neutral flux of 50,000,000 per sq cm s sr was observed, assuming hydrogen with greater than 1-keV energy, with greater north-south extent than the electron flux. Its pitch angle distribution was peaked toward 90 deg, tending toward isotropy in the center. This is fitted to a model describing spreading of an initial proton arc above 500 km.
Iglesias, G. E.↗
Access of solar electrons to the polar regions
Riometric and forward-scatter radio-wave absorption measurements at high polar latitudes in both hemispheres are compared with absorption calculations based on satellite observations in the magnetosheath to determine whether a north-south asymmetry in the solar electron flux occurred during a polar-cap absorption (PCA) event. Detection of solar electrons in interplanetary space is shown to have occurred simultaneously with detection of HF radio-wave absorption, indicating that the initial stage of the PCA was due to the arrival of solar electrons. A north-south asymmetry is observed in the electron flux, and it is found that the flux precipitating over the South Pole did not exceed the mean unidirectional intensity of the electrons detected in space. The ratio between fluxes in the low and high polar latitude regions over Antarctica during a period of solar electron anisotropy is found to be comparable with that obtained during periods of isotropy. These results are shown to be consistent with the idea of an open magnetosphere and with the conclusion that an anisotropic solar electron flux may be rendered isotropic at the magnetopause.
Nielsen, E.↗
Momentum distributions of isotopes produced by fragmentation of relativistic C-12 and O-16 projectiles
The fragment momentum distributions in the projectile rest frame are, typically, Gaussian shaped, narrow, consistent with isotropy, depend on fragment and projectile, and have no significant correlation with target mass or beam energy. The nuclear temperature is inferred from the momentum distributions of the fragments and is approximately equal to the projectile nuclear binding energy, indicative of small energy transfer between target and fragment.
Greiner, D. E.↗
X-ray binaries in globular clusters
It appears to be very unlikely that primordial binaries in globular clusters have evolved to produce high-luminosity X-ray sources like the four variable sources detected by the Uhuru and OSO-7 satellites. It is suggested that the cluster X-ray sources are binaries formed by capture from the remnants of massive single stars that exploded with sufficient isotropy to remain bound in the cluster. These remnants have lurked near the centers of the clusters where the high stellar densities have favored their capture of field stars which eventually turn the remnants on as X-ray sources when the captives enter the post-main-sequence expansion phase of their evolution. A case is made for the conclusion that there is approximately one potential binary X-ray source near the center of each of the globular clusters.
Clark, G. W.↗