SEARCH · Engineering Papers
Results for “Solar corona”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Solar coronal effects on pulsar signals.
Solar corona delay effects on pulsar signals due to inhomogeneities in coronal electron density
Direct measurements of interplanetary magnetic fields and plasmas.
Solar wind existence verified by direct measurements of interplanetary magnetic field and plasma, reviewing solar corona studies by satellites and space probes
The Surveyor lunar landings.
Surveyor lunar landing procedures and results including instrumentation, lunar topography, selenology, chemical and physical properties, solar corona and earth laser output observations
Two-photon processes in the solar X-ray spectrum.
Two photon decay of metastable levels of hydrogenic and He-like ions in solar corona, depopulating via proton collisional excitation to 2p level
Analysis of Coronal Line Profiles Final Report
Fabry-Perot interferometer measurements of emission line profiles in solar corona
Magnetic-quadrupole radiation and solar coronal de-excitation
Transition probabilities computed for spectral lines due to magnetic quadrupole radiation, discussing deexcitation of excited atoms in solar corona
The excitation of the forbidden coronal lines. I
Excitation of ground configuration of Fe XIII for density and temperature range in solar corona, using proton collisions, electron collision strengths, etc
Flare identification associated with coronal disturbances
Solar flares responsible for Faraday rotation events observed in passage of Pioneer 6 radio signal through solar corona
The spectrum of the inner corona observed during the total solar eclipse of 30 May 1965
Solar inner corona forbidden emission lines and continuum enhancement during 30 May 1965 eclipse as function of heliocentric position angle
Time variability of the dispersion of the Crab Nebula pulsar
Time variable dispersion of Crab Nebula pulsar, showing coincidence with occultation by solar corona
Recent developments in theory of solar wind
Solar wind theory, discussing thermal conduction and MHD wave energy supply mechanisms of large scale solar corona expansion
Helium-like line emission from coronal features
Solar corona O VII and Ne IX helium line triplets observations, examining electron density limits
Astronomical photography, part T
Photographic observations of astronomical interest conducted during the Apollo 15 mission are discussed. Procedures used in photographing the solar corona are described together with calibration and reduction methods. In addition, selected preliminary results obtained from the photography are presented.
The coronal transport of the flare associated scatter free electrons
A total of 11 scatter-free electron events from McMath plage region 8905 were observed by IMP 4 during the period from 29 July to 3 August 1967. The transit times and duration of these electron events are examined in detail. The duration of 170- to 1000-keV electrons shows a strong dependence upon the heliolongitude of the associated flare. Typical values of the duration full width at half maximum vary from 4 min at 50 deg W to 12 min at 10 deg and 90 deg W heliolongitudes. In addition, the difference in times at which the maximum intensities of the 22- to 45-keV and 170- to 1000-keV electrons occur is observed to change from 18 min near 50 deg W to 13 min at 10 deg and 90 deg W heliolongitudes. An idealized two-dimensional diffusion model for the transport of these electrons in the solar corona is proposed. The 22- to 45-keV electrons escape promptly from flare site to the feet of the interplanetary magnetic field lines, whereas 170- to 1000-keV electrons suffer slight scattering. The diffusion coefficient for 170- to 1000-keV electrons is estimated to be 3 X 10 to the 18th power sq cm/sec. Finally, a possible relation between the scatter-free and the classical diffusive-type electron events is discussed.
Solar-wind structure determined by corotating coronal inhomogeneities. II - Arbitrary perturbations.
The problem of the solar-wind structure resulting from long-lived inhomogeneities in the solar corona has been extended within the framework of a linearized hydrodynamic approach to allow for arbitrary perturbations in the plasma parameters, namely, velocity, density, and temperature. By using a Parker model for the zero-order flow speed, solutions are given for perturbations imposed at the zero-order critical point. Using the restriction that the solutions must be regular at the critical point, it is possible to express all situations as a linear sum of the solutions for pure velocity, density, and temperature perturbations at the critical point. The results of the integrations for three inner-boundary conditions can be used as the elements of matrices that map arbitrary perturbations at one heliocentric distance to any other distance. One interesting feature of the solutions is that the amplitudes at earth for the pure initial temperature situation are larger than for the other two situations.
The radio astronomy explorer satellite, a low-frequency observatory.
The RAE-1 is the first spacecraft designed exclusively for radio astronomical studies. It is a small, but relatively complex, observatory including two 229-meter antennas, several radiometer systems covering a frequency range of 0.2 to 9.2 MHz, and a variety of supporting experiments such as antenna impedance probes and TV cameras to monitor antenna shape. Since its launch in July, 1968, RAE-1 has sent back some 10 billion data bits per year on measurements of long-wavelength radio phenomena in the magnetosphere, the solar corona, and the Galaxy. In this paper we describe the design, calibration, and performance of the RAE-1 experiments in detail.
Rocket observations of solar UV radiation during the eclipse of 7 March 1970.
Results of observations of the solar eclipse of Mar. 7, 1970, with photometers sensitive to narrow bands of radiation at Lyman-alpha (1216 A) and at 2600 A included in the payloads of four Nike Apache rockets flown before and during the eclipse. At the center of totality, the flux of Lyman-alpha from the solar corona is 0.15% of the flux from the unobscured sun. The flux at second contact is 0.64%; at third contact, two observations give 0.52 and 0.59%. The brightness of the chromosphere in Lyman-alpha decreases exponentially over the range from 5 to 30 arc-sec from the limb with a scale height of 3835 plus or minus 70 km. In addition to the coronal and chromospheric Lyman-alpha a diffuse source is found. This is restricted to within 20 deg of the earth's horizon and is nearly uniform in azimuth at 170 km, the flux is about 3% of that from the unobscured sun. The flux of Lyman-alpha during the eclipse is considered in relation to the observed variation in electron density. It is concluded that, in totality, the ionosphere near 80 km is not in equilibrium with the ionizing radiation and that the production rate for electrons is not negligible if the loss process is recombination; it is negligible if the loss process is attachment-like.