GLORIA

GEOMAR Library Ocean Research Information Access

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
    Evidence for band-gap narrowing effects in Be-doped, p-p+ GaAs homojunction barriers (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 6361-6364 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical performance of Be-doped, p-p+ GaAs homojunction barriers is characterized and analyzed. The results of the analysis show that minority-carrier electrons, at 300 K, have a mobility of 4760 cm2/V s at a hole concentration of 2.3×1016 cm−3, and that the effective recombination velocity for these homojunction barriers is about 6×104 cm/s. We present evidence that this unexpectedly high recombination velocity is a consequence of an effective reduction in band gap due to the heavy impurity doping. The effective band-gap shrinkage in this Be-doped material grown by molecular-beam epitaxy appears to be comparable to that already observed for Zn-doped GaAs grown by metalorganic chemical vapor deposition. This work demonstrates that so-called band-gap narrowing effects significantly influence the electrical performance of GaAs devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.342102
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The identification of ^1^6O^1^8O^1^6O and ^1^6O^1^6O^1^8O ozone isotopes in high resolution ground-based FTIR spectra
    Amsterdam : Elsevier
    Journal of Quantitative Spectroscopy and Radiative Transfer 52 (1994), S. 267-271 
    Details
    ISSN: 0022-4073
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0022-4073(94)90156-2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Filament formation
    Amsterdam : Elsevier
    Advances in Space Research 13 (1993), S. 95-104 
    Details
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0273-1177(93)90463-L
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Relationship between a spot and a filament observed during spacelab 2 mission
    Amsterdam : Elsevier
    Advances in Space Research 10 (1990), S. 195-199 
    Details
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0273-1177(90)90228-R
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Sites of flares and filaments in solar active regions
    Amsterdam : Elsevier
    Advances in Space Research 13 (1993), S. 119-122 
    Details
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0273-1177(93)90466-O
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Relationship between magnetic field evolution and flaring sites in AR 6659 on June 1991
    Amsterdam : Elsevier
    Advances in Space Research 13 (1993), S. 123-126 
    Details
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0273-1177(93)90467-P
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    A model for an inverse-polarity prominence supported in a dip of a quadrupolar region (1993)
    Springer
    Solar physics 144 (1993), S. 283-305 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate the formation and support of solar prominences in a quadrupolar magnetic configuration. The prominence is modeled as a current sheet with mass in equilibrium in a two-dimensional field. The model possesses an important property which is now thought to be necessary, namely that the prominence forms within the dip, rather than the dip being created by the prominence. The approach of two bipolar regions of the same sign gives a natural way to form a dip in the magnetic field in a horizontal band above the photospheric polarity inversion line. As the approach proceeds, the height of the dip region decreases but, in agreement with observations, a corridor, free of significant magnetic field, is needed in order to obtain a dip at low heights. Support is achieved locally just as for normal-polarity configurations, so the model avoids the strong self-pinching effect of several inverse-polarity configurations (such as the Kuperus and Raadu model). The role of the strong field component along the prominence axis, which is here modelled by a uniform field in that direction, may well be to provide the necessary thermal properties for prominence formation. The model thus has several attractive features which make it credible for inverse polarity prominences: (i) both the dip and the inverse orientation are naturally present; (ii) prominence formation is by converging rather than shearing motions, in agreement with observations; converging photospheric motions induce a horizontal upward motion in the filament; (iii) the orientation of the axial field, opposite to what is expected from differential rotation, is naturally accounted for; (iv) the observed relation between chromospheric and prominence magnetic field strengths is naturally reproduced; (v) the field configuration is more complex than a simple bipole, in agreement with observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627594
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The Importance of Photospheric Intense Flux Tubes for Coronal Heating (1997)
    Springer
    Solar physics 175 (1997), S. 123-155 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Dissipation of magnetic energy in the corona requires the creation of very fine scale-lengths because of the high magnetic Reynolds number of the plasma. The formation of current sheets is a natural possible solution to this problem and it is now known that a magnetic field that is stressed by continous photospheric motions through a series of equilibria can easily form such sheets. Furthermore, in a large class of 3D magnetic fields without null points there are locations, called ‘quasi-separatrix layers’ (QSLs), where the field-line linkage changes drastically. They are the relevant generalisation of normal separatrices to configurations without nulls: along them concentrated electric currents are formed by smooth boundary motions and 3D magnetic reconnection takes place when the layers are thin enough. With a homogenous normal magnetic field component at the boundaries, the existence of thin enough QSL to dissipate magnetic energy rapidly requires that the field is formed by flux tubes that are twisted by a few turns. However, the photospheric field is not homogeneous but is fragmented into a large number of thin flux tubes. We show that such thin tubes imply the presence of a large number of very thin QSLs in the corona. The main parameter on which their presence depends is the ratio between the magnetic flux located outside the flux tubes to the flux inside. The thickness of the QSLs is approximately given by the distance between neighbouring flux tubes multiplied by the ratio of fluxes to a power between two and three (depending on the density of flux tubes). Because most of the photospheric magnetic flux is confined in thin flux tubes, very thin QSLs are present in the corona with a thickness much smaller than the flux tube size. We suggest that a turbulent resistivity is triggered in a QSL, which then rapidly evolves into a dynamic current sheet that releases energy by fast reconnection at a rate that we estimate to be sufficient to heat the corona. We conclude that the fragmentation of the photospheric magnetic field stimulates the dissipation of magnetic energy in the corona.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004986503291
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A topological approach to understand a multiple-loop solar flare (1995)
    Springer
    Solar physics 161 (1995), S. 103-121 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We analyze the UV and X-ray data obtained by the SMM satellite for the flare starting at 02:36 UT on November 12, 1980 in AR 2779. From a detailed revision of the Ov emission, we find that the observations are compatible with energy being released in a zone above the magnetic inversion line of the AR intermediate bipole. This energy is then transported mainly by conduction towards the two distant kernels located in the AR main bipole. One of these kernels is first identified in this paper. Accelerated particles contribute to the energy transport only during the impulsive phase. We model the observed longitudinal magnetic field by means of a discrete number of subphotospheric magnetic poles, and derive the magnetic field overall topology. As in previous studies of chromospheric flares, the Ov kernels are located along the intersection of the computed separatrices with the photosphere. Especially where the field-line linkage changes ‘discontinuously’, these kernels can be linked in pairs by lines that extend along separatrices. Our results agree with the hypothesis of magnetic energy released by magnetic reconnection occurring on separatrices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00732087
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Helical structures around quiescent solar prominences computed from observable magnetic fields (1992)
    Springer
    Solar physics 142 (1992), S. 291-311 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We analyse the magnetic support of solar prominences in two-dimensional linear force-free fields. A line current is added to model a helical configuration, well suited to trap dense plasma in its bottom part. The prominence is modeled as a vertical mass-loaded current sheet in equilibrium between gravity and magnetic forces. We use a finite difference numerical technique which incorporates both vertical photospheric and horizontal prominence magnetic field measurements. The solution of this mixed boundary problem generally presents singularities at both the bottom and top of the model prominence. The removal of the singularities is achieved by superposition of solutions. Together with the line current equilibrium, these three conditions determine the amplitude of the magnetic field in the prominence, the flux below the prominence and the current intensity, for a given height of the line current. A numerical check of accuracy in the removal of singularities, is done by using known analytical solutions in the potential limit. We have investigated both bipolar and quadrupolar photospheric regions. In this mixed boundary problem the polarity of the field component orthogonal to the prominence is mainly fixed by the imposed height of the line current. For bipolar regions above (respectively below) a critical height the configuration is inverse (respectively normal). For quadrupolar regions the polarity is reversed if we refer the prominence polarity to the closest photospheric polarities. We introduce the polarity of the component parallel to the prominence axis with reference to a sheared arcade. Increasing the shear with fixed boundary conditions can increase or decrease the mass supported depending on the configuration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151455
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...