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At least 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Double scattering corrections for the theory of the sun's aureole

Double scattering corrections for aureole radiances are calculated by adding the effects of two successive single scatterings. Atmospheric absorption, polarization, and variation of refractive index with altitude are ignored. Corrections due to spherical atmosphere were taken into account by the use of a generalized Chapman function. Realistic scattering phase functions based upon the Lorenz-Mie theory and model altitude-size distribution are used. The model distribution is assumed to be representable in terms of two separable particulate components. It was found that for a moderately clear day, tau (0) is approximately equal to 0.5, and for forward scattering angles, the radiance, B sub 2, due to double scattering is less than 6 percent of that due to single scattering.

Deepak, A.↗
NASA NTRS1973

Thermally driven mass flows in the convection zone of the sun

A formulation of the fluid dynamics of convective regions is developed which leads to an analytical description of the solar rotation, the Evershed flow, and the supergranulation. The starting point of the present formulation is the mixing length picture of convective equilibrium, but the earlier point mass model for convective molecules is replaced here by a model with both inertia and intrinsic moment of inertia. This extension introduces three rotational degrees of freedom into the dynamics of individual convective molecules, which enter into the dynamical equations for a mixing length fluid in the form of a separate vector field which we term the spin field. It is shown that for convective molecules having a spherically symmetric mass distribution, the spin field is proportional to the local vorticity.

Dijkhuis, G. C.↗
NASA NTRS1974

Correlations and linkages between the sun and the earth's atmosphere: Needed measurements and observations

A summary of needed measurements and observations is reported to identify the sequence of processes leading from change in solar input to change in tropospheric circulation and weather. Changes in the solar electromagnetic radiation have to be carefully monitored since variations over the solar cycle are small (less than one percent). It is suggested that changes in the ionization at the Pfotzer maximum could influence the formation of thunderstorms by changing the electric potential gradient. This could be checked by measuring the global atmospheric electric field. As an example of spacecraft observations, a worldwide distribution plot of nocturnal thunderstorms compiled from OSO-5 data shown; no obvious correlation with solar data had been found, but the time span of the data is rather limited and more sophisticated observation techniques could be used. Continuous and careful monitoring is recommended of the input of electromagnetic and particle radiation into the earth's atmosphere ozone distributions in the region above 30 km, and wind systems in the mesosphere and lower thermosphere. In addition, special phenomena suspected to be important in the causal chain, such as cirrus cloud formation at high latitudes and thunderstorm activity, should be monitored on a global basis.

Kellogg, W. W.↗
NASA NTRS1974

Energetic particles from the sun

Discussion of solar cosmic ray phenomena and related topics from the solar physical point of view. Since solar cosmic rays are usually produced by solar flares, it is necessary to understand the processes and mechanism of solar flares, especially the so-called proton flares, in order to understand the acceleration mechanism of solar cosmic rays and their behavior in both the solar atmosphere and interplanetary space. For this reason, a detailed discussion is given of various phenomena associated with solar flares, proton flare characteristics, and the mechanism of solar flares. Since the discovery of solar cosmic rays by Forbush, the interplanetary space has been thought of as a medium in which solar cosmic rays propagate. The propagation of solar cosmic rays in this space is therefore discussed briefly by referring to the observed magnetic properties of this space. Finally, some problems related to the physics of galactic cosmic rays are discussed.

Sakurai, K.↗
NASA NTRS1974

The energy crisis and energy from the sun; Proceedings of the Symposium on Solar Energy Utilization, Washington, D.C., April 30, 1974

Papers on the state of the art and future prospects of solar energy utilization in the United States are included. Research and technologies for heating and cooling of buildings, solar thermal energy conversion, photovoltaic conversion, biomass production and conversion, wind energy conversion and ocean thermal energy conversion are covered. The increasing funding of the National Solar Energy Program is noted. Individual items are announced in this issue.

Thekaekara, M. P.↗
NASA NTRS1974

High resolution interferometry of the sun at 3.7 cm wavelength

The results of interferometric solar observations at a wavelength of 3.7 cm with effective resolutions of 7 and 15 sec are discussed. Observations have shown that a small-scale quasi-periodic component was present in solar radio emission from the entire solar disk and that this component contained a circularly polarized fraction of less than 10%. The theory of gyroradiation and gyro-resonant absorption is applied in the interpretation of the S-component of solar radio emission.

Lang, K. R.↗
NASA NTRS1974

Solar particles /observations, relationship to the sun acceleration, interplanetary medium/

The major features of the propagation of flare particles in the interplanetary medium are discussed in terms of the classic well-behaved flare having unique impulsive injection and a smooth time profile. Topics include flare events, their frequency of occurrence, development of a typical event, energy spectra, proton and electron types, charge and isotopic composition, solar flares and particle accelerations, radio and X-ray observations, the Fermi mechanism, the betatron mechanism, acceleration models, plasma instabilities, two-stage acceleration, propagation mechanisms, the anisotropic stage, the diffusive stage, and the convection and energy loss stage.

Mcdonald, F. B.↗
NASA NTRS1975

Wide-angle sun sensors

Two sensors have been developed: one, single-axis device, is cylindrical; the other, two-axis device, is spherical. Multiple surface deposits of photosensitive material, such as cadmium sulfide, serve as redundancy, ensuring high reliability.

Schumacher, L. L.↗
NASA NTRS1975

Forbidden Ca 2 in the sun unmasked by way of Venus

Eleven high-dispersion spectra of Venus, taken with blue Doppler shifts have permitted the unmasking of the 7323.88A forbidden line of Ca II from terrestrial absorption. An equivalent width is obtained of 7.4 + or - 0.4mA for this line in integrated sunlight. Our value of W sub lambda is smaller than previous values and much more accurate. The HSRA solar model gives a solar calcium abundance of A sub Ca = 6.21.

Schorn, R. A.↗
NASA NTRS1975

The interstellar medium near the sun - The line of sight to lambda Scorpii

Copernicus satellite spectrometric observations are used to determine column densities and ionization structure in the local interstellar medium in the line of sight to lambda Sco. Three, or possibly four, regions are identified by physical properties or velocity separations in the UV absorption line profiles, including a region with a temperature near 200,000 K containing O VI lines, one or two H II regions, and an H I region which may also contain S III and C III. Element abundances are tabulated, and abundances in the H I region are shown to have a depletion pattern similar to that for the line of sight to zeta Oph.

York, D. G.↗