ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Microwave and hard X-ray imaging of a solar flare on 1980 November 5 (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: VLA and SMM hard X ray data on the solar flares of November 5, 1980 are analyzed and compared with data from other sources. The VLA provided measurements at 15 GHz at 10 sec intervals, using left and right circular polarizations with a 0.6 arcsec resolution. The hard X ray imaging spectrometer on the SMM obtained data in six bands from 3.5-30 keV, with 8 x 8 arcsec resolution and 1.5 sec separation. The data were examined for a possible nonthermal source for the microwave component of the emissions detected, the origin of 16-30 keV excess fluxes, the relation between the X ray and microwave sources, the magnetic connection between observed loops, and the physical characteristics of the radiating loop. The data were consistent with a model that assumes fast electrons are accelerated to a single power-law energy distribution and freely stream along the magnetic field. The data also agreed with a thick-target model for solar flare X ray emission.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 268; May 15
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    VLA observations of impulsive solar flares at 4.9 GHz (1980)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A series of snapshot synthesis maps constructed as a function of time provided a complete mapping of source structure in one dimension and absolute location in two dimensions of five impulsive solar microwave bursts observed during July 15-18, 1978. It was found that all five flares were dominated by a single 12-18 arcsec source located between the H-alpha kernels, near the magnetic neutral line. Spectral data from Sagamore Hill (1.4-35 GHz) show that the spectral turnover at low frequencies results from the absorption by the ambient active region; these results, together with the observed magnetic configuration, suggest a model which could explain the evolution in source structure at 4.9 GHz in terms of magnetic reconnection which starts below the optical depth of the ambient active region equal to 1.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 242
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Properties of solar flare electrons, deduced from hard X-ray and spatially resolved microwave observations (1981)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: An important question concerning an understanding of impulsive solar flares is related to the energetic electrons responsible for the microwave and the hard X-ray emission. A description is presented of an investigation in which spatially resolved microwave observations of an impulsive flare and hard X-ray data from the Solar Maximum Mission (SMM) are used to test the hypothesis that the two types of emission come from the same basic electron population. The considered observations are found to imply that the microwaves and hard X-rays were not produced by a common population of electrons with either a Maxwellian or single power-law energy distribution. It is suggested that the calculations should be repeated when observations of stronger events become available, for which a better determination of the X-ray spectrum is possible. The possibility is considered that microwaves and moderately hard X-rays come from spatially different regions.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 251
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    VLA observations of solar flares, interpreted with optical, X-ray, and other microwave data (1979)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 228
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    The lifetime and evolution of fibrils (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A detailed study was made of the lifetimes and evolution of fibrils in McMath 12417, using high resolution filtergrams in H alpha and CaII K made at Big Bear Solar Observatory. It was found that the lifetime of a fibril increases monotonically with its length. This relationship, together with the form of the variation of fibril lengths as a function of time, suggests that fibrils result from material being impulsively injected into magnetic field lines at approximately 30 km/sec, and returning under gravity. The lifetimes and apparent lengths of fibrils are then a function of the inclination of the field lines only. A study of wavelength scans through the H alpha line confirms that the apparent expansion and contraction of fibrils represents true mass motion.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-147103 , BBSO-0156
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    VLA observations of spatial structure in the quiet sun at 6 centimeters, during the 1977 October eclipse (1980)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 236
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Two-dimensional VLA maps of solar bursts at 15 and 23 GHz with arcsec resolution (1980)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Three small, impulsive solar-microwave bursts (peak fluxes 4.9, 3.0, and 0.4 sfu) were observed during 1979 September 7-9, using the Very Large Array (VLA) at 15.05 or 22.5 GHz. The data from 10 antennas distributed on three arms of the array provide the first two-dimensional burst images with spatial resolution as high as 1.0 x 0.75 arcsec. Comparison with optical data showed in the impulsive phase of all three flares, the microwave emission was dominated by a compact source located between the H-alpha kernels. In the post-impulsive phase, the microwave source was larger and elongated in a direction consistent with the orientation of the magnetic field lines joining the H-alpha kernels. These results are interpreted to imply that the initial energy release occurs near the top of the magnetic arch joining the H-alpha kernels.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 240
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    The calcium K-line network in coronal holes (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: Microphotometry of calcium K-line photographs in the regions of polar coronal holes shows that the chromospheric network exterior to a hole has a slightly broader intensity distribution than that inside the hole itself, a fact which can be attributed to a greater number of bright network elements outside the hole. These bright elements presumably represent the enhanced network resulting from the dispersal of magnetic flux from old active regions, a hypothesis which is consistent with current ideas of coronal-hole formation.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 52; May 1977
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    The lifetime and evolution of fibrils (1976)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: A detailed study has been made of the lifetimes and evolution of fibrils in McMath 12417, using high resolution filtergrams in H-alpha and Ca II K. It was found that when viewed near disk center, the lifetime of a fibril is a monotonically increasing function of its maximum apparent length. This relationship, together with the form of the variation of fibril lengths as a function of time, suggests that fibrils result from material being impulsively injected into magnetic field lines at approximately 30 km/sec, and returning under gravity. The lifetimes and apparent lengths of fibrils are then a function of the inclination of the field lines only. A study of wavelength scans through the H-alpha line confirms that the apparent extension and retraction of fibrils represents true mass motion.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 50; Sept
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    High resolution interferometric observations of the solar limb at 4.9 and 10.7 GHz during the solar eclipse of October, 1977 (1981)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The radial intensity profile of the quiet solar limb has been measured at high spatial resolution using the VLA at 4.9 GHz and the Owens Valley solar interferometer at 10.7 GHz during the partial solar eclipse of October 12, 1977. The spatial resolution (13.8 arcsec at 4.9 GHz and 7.4 arcsec at 10.7 GHz) was provided primarily by the lunar limb. Substantial limb brightening at 4.9 GHz was found with a peak brightness temperature corresponding to an 80% increase over the disk value, and a possible small limb enhancement at 10.7 GHz. The results are consistent with a simple model consisting of a uniform disk (provided by a thoroughly roughened transition zone) overlaid by a corona in hydrostatic equilibrium with a density of 5 x 10 to the 8th at its base. The lack of the secant-like variation in the microwave intensity from center to limb is explained by a corona contained in loop structures rather than in spherically symmetric layers.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 94; 1, Ja; Jan. 198
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...