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
    Electronic Resource
    Electronic Resource
    Comparison of coronal holes observed in soft X-ray and He i 10 830 Å spectroheliograms (1983)
    Springer
    Solar physics 87 (1983), S. 47-56 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We compare coronal holes observed in solar soft X-ray images obtained with rocket-borne telescopes during 1974 to 1981 with holes observed on nearly simultaneous 10830 Å maps. Hole boundaries are frequently poorly defined, and after 1974 the brightness contrast between the large scale structure and holes appears substantially diminished in both X-rays and 10830 Å. We find good agreement between soft X-rays and 10830 Å for large area holes but poor agreement for mid and low latitude small area holes, which are generally of low contrast. These results appear inconsistent with the popular view that the quiet corona is sharply separated into open magnetic field regions consisting of coronal holes and closed field regions consisting of the large scale structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151159
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The spatial distribution of 6 centimeter gyroresonance emission from a flaring X-ray loop (1984)
    Springer
    Solar physics 92 (1984), S. 271-281 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We compare simultaneous high resolution soft X-ray and 6 cm images of the decay phase of an M3 X-ray flare in Hale Region 16413. The photographic X-ray images were obtained on an AS & E sounding rocket flown 7 November, 1979, and the 6 cm observations were made with the VLA. The X-ray images were converted to arrays of line-of-sight emission integrals and average temperature throughout the region. The X-ray flare structure consisted of a large loop system of length ∼ 1.3 arc min and average temperature ∼8 × 106 K. The peak 6 cm emission appeared to come from a region below the X-ray loop. The predicted 6 cm flux due to thermal bremsstrahlung calculated on the basis of the X-ray parameters along the loop was about an order of magnitude less than observed. We model the loop geometry to examine the expected gyroresonance absorption along the loop. We find that thermal gyroresonance emission requiring rather large azimuthal or radial field components, or nonthermal gyrosynchrotron emission involving continual acceleration of electrons can explain the observations. However, we cannot choose between these possibilities because of our poor knowledge of the loop magnetic field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00157251
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    X-Ray and microwave observations of active regions (1983)
    Springer
    Solar physics 85 (1983), S. 267-283 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We compare coordinated, high spatial resolution (2–3 arc sec) observations at 6 cm and in soft X-rays with photospheric magnetograms and optical filtergrams of two active regions. The correspondence of the brightest centimetric components in these regions with coronal loops, sunspots and pores, chromospheric structures and the photospheric magnetic field was determined. Our principal results are: The association between the microwave components and coronal X-ray and photospheric magnetic field structures is complex; in general X-ray emission was not associated with the microwave components. A majority of the components were not associated with sunspots, although the brightest (T b ≥ 4 × 106 K) components overlay regions of strong photospheric field or high field gradients. Several of the components coincided with the apparent bases of shorter coronal loops and 4 with the tops of X-ray loops. The X-ray and magnetic field observations are used to constrain possible centimetric emission mechanisms. Thermal bremsstrahlung can not be a significant contributor to this bright microwave emission. Thermal gyro-resonance absorption is consistent with some of the observations, but untenable for those components which are bright in microwaves, lack X-ray emission, and overlie regions of weak magnetic field. As an explanation for the brightest (T b ≥ 4 × 106 K) components, the g-r theory requires coronal loops with significant currents but very low densities. Alternatively, a nonthermal mechanism implies that the emission arises from the transition region and suggests that discrete regions of continuous particle acceleration may be common in active regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00148654
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Concanavalin A receptors and capping in control and activated macrophages (1983)
    Springer
    Journal of molecular histology 15 (1983), S. 59-69 
    Details
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Macrophages activatedin vivo withCorynebacterium parvum and asbestos showed an increased sub-population of cells which capped spontaneously on incubation with fluoresceinated Concanavalin A compared to saline-induced control macrophages. This capping was unaffected by colchicine but was inhibited by cytochalasin B. The spontaneous capping of activated macrophages did not appear to be directly related to the total number of Concanavalin A receptors as measured by specific125I-labelled Concanavalin A binding to activated and control macrophages. Capping also did not appear to be related to the position of Concanavalin A receptors as judged by trypsin accessibility of bound125I-labelled Concanavalin A.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01006071
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    A wind tunnel study of the flow field within and around open-top chambers used for air pollution studies (1983)
    Springer
    Boundary layer meteorology 25 (1983), S. 193-214 
    Details
    ISSN: 1573-1472
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The EPA Meteorological Wind Tunnel was used to examine the flow field in and around models of open-top field-plant growth chambers used to assess the effects of pollutant gases on plant growth. Baffles designed to reduce the ingress of ambient air into the chamber through the open top were tested; the mean flow and turbulence in the simulated boundary layer with and without the chambers were compared (the chamber was operated with and without the pollutant flow system on); and the effects of surrounding chambers on the concentration field were measured. Results showed that a baffle with a reduced opening vertically above the test area maintained the highest uniform concentration in the test area. The major differences between the three (no chamber and the chamber with flow on and off) mean velocity profiles occurred below z/h = 2.0 (h is chamber height) and at z/h ≤ 4.2. The three Reynolds stress profiles were similar above z/h = 2.0. Downwind of the chamber, the Reynolds stresses in the on-mode were greater than those in the off-mode above z/h = 1.1. The reverse was true below that point. Both longitudinal and vertical intensities above and downwind of the chamber were greater with the mixture flow system on rather than off, below about z/h 〈 1.5. Lateral variations in the mean wind indicated that the mean velocity was greater with the mixture flow system on except near the centerline where the reverse was true. The concentrations in the downwind wake resembled those for a cube. The location of a cylinder within a regular array had some effect on its internal gas concentration. Locations near the upwind and downwind edges of the array were associated with lower concentrations, although for all locations the highest internal values were always found at the lowest portion of the upwind wall. With active cylinders downwind, the gas plume emitted from a source cylinder at the windward edge of the array was forced 0.5 h higher and the centerline meandered laterally when compared with the single-cylinder case. A cylinder located at z/h = 1.0 downwind from a source cylinder received approximately 3%; of the concentration input to the source, or roughly 10%; of the actual concentration within the source cylinder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00123974
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A regional analysis of the meteorological aspects of the spread and development of blue mold on tobacco (1984)
    Springer
    Boundary layer meteorology 28 (1984), S. 271-304 
    Details
    ISSN: 1573-1472
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Tobacco blue mold caused by Peronospora tabacina is a highly weather sensitive disease which occurred in the major tobacco production areas of North Carolina in 1980. Dates of first reported occurrence of blue mold by county units in eastern North Carolina progressed in a northeastward direction from the South Carolina border to the Virginia border between 1 May and 6 June. In the central piedmont region of the state, blue mold was first reported in mid-May while in the western mountains, blue mold was recorded in early June. Temperatures and total weekly rainfall data were analyzed for 18 weeks from late March to early August from 102 weather stations across North Carolina and from the bordering regions of surrounding states. An analysis of first occurrence dates and the temporal and spatial properties of temperature and precipitation indicated that the epidemic continued to spread despite temperatures outside the range previously considered favorable for the disease. Availability of moisture on the tobacco leaves for spore germination appeared to be the predominant factor in all parts of the state. Trajectory analysis was used to identify possible source regions for the spores which arrived over North Carolina tobacco fields. The analysis indicated that there were many days in April, May, and June 1980 when conditions were considered favorable for spore transport to North Carolina from the infected fields located to the south. Taking into account epidemiological latent periods, certain of these trajectory dates were selected as representing the most probable periods of spore transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00121308
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Observations of the reappearance of polar coronal holes and the reversal of the polar magnetic field (1984)
    Springer
    Solar physics 92 (1984), S. 109-132 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We examine observations relating to the evolution of the polar magnetic field around sunspot maximum, when the net polar flux reverses polarity and coronal holes redevelop around the poles. Coronal hole observations during the last two solar maxima are examined in detail. Long-term averages of the latitudinal dependence of the photospheric magnetic field and the evolutionary pattern of the polar crown filaments are used to trace the poleward motion of the reversal of the large-scale surface field, and are compared to the redevelopment of the polar holes. The polar holes evolve from small, mid-latitude holes of new-cycle polarity which expand poleward until they join and cover the pole. We find that the appearance of these mid-latitude holes, the peak of flux emergence at low latitudes, and the polar polarity reversal all occur within a few solar rotations. Lagging 6 months to 1 1/2 yr after this time, the polar crown disappears and the polar holes redevelop. These results are examined in the context of phenomenological models of the solar cycle. We believe the following results in particular must be accounted for in successful models of the solar cycle: (1) The process of polarity reversal and redevelopment of the polar holes is discontinuous, occurring in 2 or 3 longitude bands, with surges of flux of old-cycle polarity interrupting the poleward migration of new-cycle flux. There is a persistent asymmetry in these processes between the two hemispheres; the polarity reversal in the two hemispheres is offset by 6 months to 1 1/2 yr. (2) Contrary to the Babcock hypothesis, the polar crown disappears months after the magnetic polar reversal. We suggest one possible scenario to explain this effect. (3) Our observations support suggestions of a poleward meridional flow around solar maximum that cannot be accounted for by Leighton-type diffusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00157239
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Flare research with the NASA/MSFC vector magnetograph: Observed characteristics of sheared magnetic fields that produce flares (1982)
    Springer
    Solar physics 113 (1982), S. 347-352 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The present MSFC Vector Magnetograph has sufficient spatial resolution (2.7 arcsec pixels) and sensitivity to the transverse field (the noise level is about 100 gauss) to map the transverse field in active regions accurately enough to reveal key aspects of the sheared magnetic fields commonly found at flare sites. From the measured shear angle along the polarity inversion line in sites that flared and in other shear sites that didn't flare, we find evidence that a sufficient condition for a flare to occur in 1000 gauss fields in and near sunspots is that both (1) the maximum shear angle exceed 85 degrees and (2) the extent of strong shear (shear angle 〉 80 degrees) exceed 10,000 km.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00147721
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    facet.materialart.
    Unknown
    Comparison of coronal holes observed in soft X-ray and He i 10 830 � spectroheliograms (1983)
    Springer
    Details
    Publication Date: 1983-08-01
    Print ISSN: 0038-0938
    Electronic ISSN: 1573-093X
    Topics: Physics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Observations of the reappearance of polar coronal holes and the reversal of the polar magnetic field (1984)
    Springer
    Details
    Publication Date: 1984-05-01
    Print ISSN: 0038-0938
    Electronic ISSN: 1573-093X
    Topics: Physics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...