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  • 301.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Gaia and Metal-Poor Stars2006In: ASP Conference Series, Vol. 523, p. 387-399Article, review/survey (Other (popular scientific, debate etc.))
  • 302.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Harry Martinson, Fågel Fenix och kvantelektrodynamiken2004In: 5 röster om ett författarskap, Harry Martinsonsällskapet , 2004Chapter in book (Other (popular scientific, debate etc.))
  • 303.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    IAUS 228: Concluding remarks2005In: IAUS 228, 2005, p. 603-610Conference paper (Other (popular scientific, debate etc.))
  • 304.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Livet i rymdens öde hus -- Aniara och den nutida astronomins syn på kosmos2004In: Tvärsnitt, Vol. 2, no 4Article in journal (Other (popular scientific, debate etc.))
  • 305.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Model Atmospheres and Stellar Abundance Analysis2004In: Carnegie Observatories Centennial Symposia: Origin and Evolution of the Elements, 2004Chapter in book (Refereed)
  • 306.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Nucleosynthesis and future stellar abundance determinations2004In: EAS Publ. Ser., Vol. 11, p. 21-50Article, review/survey (Other (popular scientific, debate etc.))
  • 307.
    Gustafsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Scientists should promote co-operation, not boycott2007In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 447, no 7147, p. 908-908Article in journal (Refereed)
  • 308.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Tankar om rörelsens omöjlighet och om dynamiken i fysiken2006In: Hänryckning och ohygglighet: En antologi om Margaretha Åsbergs koreografiska verk, Carlssons , 2006, p. 136-150Chapter in book (Other (popular scientific, debate etc.))
  • 309.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    The currenst status of the modelling of stellar atmospheres2003In: IAU Symposia, Vol. 210, p. 3-18Article, review/survey (Other (popular scientific, debate etc.))
  • 310.
    Gustafsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics, Theoretical Astrophysics.
    Towards a satisfactory understanding of AGB-Star Atmospheres2007In: Why galaxies care about AGB stars: Their importance as actors and probes / [ed] Kerschbaum F; Charbonnel C; Wing RF, 2007, Vol. 378, p. 60-70Conference paper (Other academic)
    Abstract [en]

    The understanding and the modelling of the atmospheres of AGB stars are discussed and found to be unsatisfactory for most purposes. A number of developments and possible actions to improve this situation are considered.

  • 311.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Vad gjorde stjärnorna före Vintergatan?2004In: Populär astronomi, Vol. 1, no 30Article in journal (Other (popular scientific, debate etc.))
  • 312.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    What could theology learn from science, and science from theology?2002In: Nathan Söderblom and the development of an academic discipline, 2002Chapter in book (Other (popular scientific, debate etc.))
  • 313.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Asplund, Martin
    Edvardsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Jonsell, Karin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Magain, Pierre
    Nissen, Poul-Erik
    Chemical abundances in 43 metal-poor stars2005In: IAUS, 2005, p. 228, 259-Conference paper (Refereed)
  • 314.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Boström, Rolf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Astronomi och rymdvetenskap2001In: Vetenskapens framsteg, 2001Chapter in book (Other (popular scientific, debate etc.))
  • 315.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Edvardsson, Bengt
    Department of Physics and Astronomy, Theoretical Astrophysics.
    Eriksson, Kjell
    Department of Physics and Astronomy, Theoretical Astrophysics.
    Gråe-Jørgensen, Uffe
    Mizuno-Wiedner, Michelle
    Department of Physics and Astronomy, Theoretical Astrophysics.
    Plez, Bertrand
    A new MARCS Grid2002In: International Astronomical Union Symposium: Modelling of Stellar Atmospheres, 2002, p. A2-Conference paper (Other scientific)
    Abstract [en]

    An extensive grid of spherically symmetric model atmospheres of stars with 1. 2500 K <= Teff <= 8000 K, 2. -1.0 <= log g (= log GM/R2) <= 5.0 (cgs units), 3. different combinations of M and R, 4. -5 <= [A/H] <= 1, and 5. a number of CNO abundance combinat

  • 316.
    Gustafsson, Bengt
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Edvardsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Libarires of synthetic stellar spectra -- or are we building palaces upon sand?2007In: IAU Symp 241, Vol. 241, p. xx-xx+10Article, review/survey (Other academic)
  • 317.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Hermeren, Göran
    Petersson, Bo
    Good research practice -- what is that?2005Book (Other (popular scientific, debate etc.))
  • 318.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Hermeren, Göran
    Petersson, Bo
    Vad är god forskningssed?: Synpunkter, riktlinjer och exempel2004Book (Other (popular scientific, debate etc.))
  • 319. Gustafsson, Bengt
    et al.
    Karlsson, Torgny
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Olsson, Emma
    Edvardsson, Bengt
    Ryde, Nils
    The origin of carbon, investigated by spectral analysis of solar-type stars in the Galactic disk1999In: Astronomy and Astrophysics, ISSN 0004-6361, Vol. 342, p. 426-439Article in journal (Refereed)
  • 320.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Astronomical observatory.
    Karlsson, Torgny
    Olsson, Emma
    Edvardsson, Bengt
    Ryde, Nils
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Astronomical observatory. Physics, Department of Astronomy and Space Physics.
    The origin of carbon, investigated by spectral analysis of solar-type stars in the Galactic Disk1999In: ASTRONOMY AND ASTROPHYSICS, ISSN 0004-6361, Vol. 342, no 2, p. 426-439Article in journal (Refereed)
    Abstract [en]

    Abundance analysis of carbon has been performed in a sample

  • 321.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Mizuno-Wiedner, Michelle
    How Good Are New Ages for Old Stars?2001In: Proceedings of "Astrophysical Ages and Times Scales" (ASP Conference Series), San Francisco: Astronomical Society of the Pacific , 2001, Vol. 245, p. 271-279Conference paper (Other scientific)
    Abstract [en]

    The accuracy obtainable with the best dating methods for old field stars is hardly better than 20% for any of the current methods. For a number of problems in the study of of the evolution of the Galactic halo and the disk, a reduction of the errors to be

  • 322.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Astronomical observatory. Physics, Department of Astronomy and Space Physics.
    Ryde, Nils
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Astronomical observatory. Physics, Department of Astronomy and Space Physics.
    The Role of Carbon Stars in the Evolution of Galaxies2000In: IAU Symposium 177: The Carbon Star Phenomenon, p. 481-496Article, review/survey (Other (popular scientific, debate etc.))
    Abstract [en]

    The role of carbon stars in the build-up of chemical elements in galaxies

  • 323.
    Gustafsson, Bengt
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Wahlin, Rurik
    The Chemical Composition of Red Giants, AGB Stars and Planetary2006In: IAUS, Vol. 234, p. 8-Article, review/survey (Other (popular scientific, debate etc.))
  • 324.
    Gustafsson, Björn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    The virtue of looking in another direction2003In: UppOR, p. 59-Article in journal (Other (popular scientific, debate etc.))
  • 325.
    Gustavsson, B., Sergienko, T., Rietveld, M.T., Honary, F., Steen, A., Brandstrom, B.U., Leyser, T.B., Aruliah, A.L., Aso, T., Ejiri, M. and Marple, S.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    First Tomographic estimate of volume distribution of HF-pump enhanced airglow emission.2001In: Journal of Geophysical Research, Vol. 106, no A12, p. 29105-29123Article in journal (Refereed)
    Abstract [en]

    This report presents the first estimates of the three-dimensional volume emission rate of enhanced O(D-1) 6300 Angstrom airglow caused by HF radio wave pumping in the ionosphere. Images of the excitation show how the initially speckled spatial structure o

  • 326.
    Guthman, Axel W.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Space Plasma Physics.
    Thidé, Bo
    The LOIS project and astrophysics.2005In: High Energy Gamma-Ray Astronomy, 2nd International Symposium: Conference Proceedings, Vol. 745, p. 770-773Article in journal (Refereed)
  • 327. Gutierrez, P
    et al.
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Non-gravitational force modeling of Comet 81P/Wild 2: II. Rotational evolution2007In: Icarus, ISSN 0019-1035, E-ISSN 1090-2643, Vol. 191, no 2, p. 651-664Article in journal (Refereed)
    Abstract [en]

    In this paper, we have studied both the dynamical and the rotational evolution of an 81P/Wild 2-like comet under the effects of the outgassing-induced force and torque. The main aim is to study if it is possible to reproduce the non-gravitational orbital changes observed in this comet, and to establish the likely evolution of both orbital and rotational parameters. To perform this study, a simple thermophysical model has been used to estimate the torque acting on the nucleus. Once the torque is calculated, Euler equations are solved numerically considering a nucleus mass directly estimated from the changes in the orbital elements (as determined from astrometry). According to these simulations, when the water production rate and changes in orbital parameters for 1997, as well as observational rotational parameters for 2004 are imposed as constraints, the change in the orbital period of 81P/Wild 2, ΔP=P˙, will decrease so that P¨=‑5 to ‑1minorbit, which is similar to the actual tendency observed from 1988 up to 1997. This nearly constant decreasing can be explained as due to a slight drift of the spin axis orientation towards larger ecliptic longitudes. After studying the possible spin axis orientations proposed for 1997, simulations suggest that the spin obliquity and argument (I,Φ)=(56°,167°) is the most likely. As for rotational evolution, changes per orbit smaller than 10% of the actual spin velocity are probable, while the most likely value corresponds to a change between 2 and 7% of the spin velocity. Equally, net changes in the spin axis orientation of 4° 8° per orbit are highly expected.

  • 328. Gutierrez, P
    et al.
    Rodrigo, R
    Ortiz, J
    Davidsson, Björn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    An investigation of errors in estimates of the cometary nuclei active area fractions2003In: Astronomy and Astrophysics, ISSN 0004-6361, Vol. 401, no 2, p. 755-761Article in journal (Refereed)
    Abstract [en]

    Active area fractions of cometary nuclei are often estimated by comparing the observed water production rates with theoretical rates obtained by applying the fast rotator or subsolar point approximations to spherical model nuclei. Any discrepancy between observed and theoretical production rates is interpreted as a certain degree of dust mantling (or in some cases hyper activity) of the object. We here investigate the typical errors introduced in such active area fraction estimates by the usage of oversimplified spherical model nuclei. This is done by first calculating the production rates of slowly rotating irregular model bodies with different activity patterns on their surfaces and arbitrary spin axis orientations, for which solar illumination is treated properly. Next, the production rates of the spherical model objects under averaged insolation are compared to the production rates of the complex model objects in an attempt to recover the known active area fraction of the latter bodies. We then find that the fast rotator and subsolar point approximations generally yield large over- and underestimates of the active area fraction, depending on the characteristics of the simulated complex nuclei. Acceptable relative errors ( <100%) only occur at small heliocentric distances, and the subsolar point approximation yields somewhat better results than the fast rotator approximation.

  • 329.
    Gutierrez, P.J
    et al.
    Instituto de Astrofísica de Andalucía-CSIC, PO Box 3004, 18080 Granada, Spain .
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Ortiz, J.L
    Instituto de Astrofísica de Andalucía-CSIC, PO Box 3004, 18080 Granada, Spain .
    Rodrigo, R.
    Instituto de Astrofísica de Andalucía-CSIC, PO Box 3004, 18080 Granada, Spain .
    Vidal-Nunez, M.J
    Instituto de Astrofísica de Andalucía-CSIC, PO Box 3004, 18080 Granada, Spain .
    Commets on the amplitude-phase relationship of asteroid lightcurves: Effects of topography, surface scattering properties, and obliquity2006In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 454, no 1, p. 367-377Article in journal (Refereed)
    Abstract [en]

    Aims. We present a theoretical study on the amplitude-phase relationship (APR) for lightcurves of simulated asteroids.

    Methods. In support of the Rosetta (ESA) mission, we developed a numerical model for the investigation of the light reflectance properties of asteroidal bodies. The code is able to deal with irregular and chemically inhomogeneous surfaces, taking shadowing effects into account. Several standard scattering models have been implemented, which govern local reflectance properties, e. g. the Hapke model and the Lumme-Bowell model. From a kinematic standpoint, the body can move in an arbitrary orbit, and it may rotate in either pure or complex mode with an arbitrary orientation of its angular momentum. As an application of the code, we studied the dependence of the APR on several factors, such as the illumination and observational geometries, overall shape, and large-scale topography, as well as the surface characteristics represented by the parameters in the Hapke and Lumme-Bowell models.

    Results. In our study, we find that mineralogy, regolith properties, and small-scale surface roughness (i. e., characteristics embodied in the considered surface scattering models), have a negligible effect on the APR. Furthermore, large-scale topography introduces a rather significant dispersion in the APR slope, on the order of 0.010 mag deg(-1). Our simulations suggest that obliquity is the major agent for shaping the APR, causing a 0.020 mag deg(-1) dispersion in the APR slope; the larger the obliquity, the smaller the slope of the APR. For intermediate aspect angles, large obliquities could even lead to an amplitude that decreases with the phase angle.

  • 330. Hahn, G.
    et al.
    Lagerkvist, C.-I.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Karlsson, O.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Oja, T.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    P/2004 A1 (Loneos) - a comet under transition from Saturn to Jupiter2006In: Astron. Nachr., Vol. 327, no 1, p. 17-20Article in journal (Refereed)
  • 331.
    Hall, J. O.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Istomin, Ya. N.
    Leyser, T. B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Electromagnetic coupling of localized upper hybrid oscillations in a system of density depletions2009In: Physics of Plasmas, ISSN 1070-664X, E-ISSN 1089-7674, Vol. 16, no 1, p. 012902-Article in journal (Refereed)
    Abstract [en]

    One of the most important effects of pumping the ionospheric plasma by a powerful high frequency electromagnetic wave from the ground is the excitation of filamentary density irregularities. These striations are density depletions which contain localized upper hybrid oscillations. The upper hybrid oscillations radiate Z mode waves that escape from the depletions and can therefore scatter on neighboring depletions, which provides a means for electromagnetic interaction between different striations. The physics of a Z mode wave scattering on a single density depletion is studied analytically in one dimension. At resonance the incident Z mode wave is totally reflected from the irregularity. The treatment of many parallel striations interacting through the Z mode radiation shows that different scattering processes are involved to excite the even and odd modes of the localized upper hybrid oscillations.

  • 332.
    Hall, Jan-Ove
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Conversion of localized lower hybrid oscillations and fast magnetosonic waves at a plasma density cavityIn: Physics of Plasmas, ISSN 1070-664XArticle in journal (Refereed)
  • 333.
    Hall, Jan-Ove
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Space Plasma Physics.
    Conversion of trappedmupper hybrid oscillation and Z mode at a plasma density irregulations2003In: Phys.Plasmas, Vol. 10Article in journal (Other (popular scientific, debate etc.))
  • 334.
    Hall, Jan-Ove
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Interaction between Electromagnetic Waves and Localized Plasma Oscillations2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two specific physical systems are considered, namely artificially excited magnetic field-aligned irregularities (striations) and naturally excited lower hybrid solitary structures (LHSS). Striations are mainly density depletions of a few percent that are observed when a powerful electromagnetic wave, a pump wave, is launched into the ionosphere. The striations are formed by upper hybrid (UH) oscillations that are localized in the depletion where they are generated by the linear conversion of the pump field on the density gradients. However, the localization is not complete as the UH oscillation can convert to a propagating electromagnetic Z mode wave. This process, termed Z mode leakage, causes damping of the localized UH oscillation. The Z mode leakage is investigated and the theory predicts non-Lorentzian skewed shapes of the resonances for the emitted Z mode radiation. Further, the interaction between individual striations facilitated by the Z mode leakage is investigated. The LHSS are observed by spacecraft in the ionosphere and magnetosphere as localized waves in the lower hybrid (LH) frequency range that coincides with density cavities. The localized waves are immersed in non-localized wave activity. The excitation of localized waves with frequencies below LH frequency is modelled by scattering of electromagnetic magnetosonic (MS) waves off a preexisting density cavity. It is shown analytically that an incident MS wave with frequency less than the minimum LH frequency inside the cavity is focused to localized waves with left-handed rotating wave front. In addition, the theory is shown to be consistent with observations by the Freja satellite. For frequencies between the minimum LH frequency inside the cavity and the ambient LH frequency, the MS wave is instead mode converted and excites pressure driven LH oscillations. This process is studied in a simplified geometry.

    List of papers
    1. Conversion of trapped upper hybrid oscillations and Z mode at a plasma density irregularity
    Open this publication in new window or tab >>Conversion of trapped upper hybrid oscillations and Z mode at a plasma density irregularity
    2003 In: Physics of Plasmas, ISSN 1070-664X, Vol. 10, no 6, p. 10-Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-91832 (URN)
    Available from: 2004-05-12 Created: 2004-05-12Bibliographically approved
    2. Electromagnetic interaction of localized upper hybrid oscillations in a system of density depletions
    Open this publication in new window or tab >>Electromagnetic interaction of localized upper hybrid oscillations in a system of density depletions
    2006 (English)In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 38, no 11, p. 2516-2517Article in journal (Refereed) Published
    Abstract [en]

    We present the results of the investigation of interaction of different depletions of plasma density by Z-mode radiation. It is shown that more profitable disposition of cavities in space is random. The amplitude of the radiated Z-mode in this case is of the order of the amplitude of the pumping ordinary wave, but the amplitude of trapped into cavities upper hybrid wave is maximum and can be significantly higher than the amplitude of the pumping wave.

    Keywords
    electromagnetic waves, ionospheric disturbances and modifications
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-91833 (URN)10.1016/j.asr.2005.02.039 (DOI)000202988800034 ()
    Available from: 2004-05-12 Created: 2004-05-12 Last updated: 2017-12-14Bibliographically approved
    3. Excitation of localized rotating waves in plasma density cavities by scattering of fast magnetosonic waves
    Open this publication in new window or tab >>Excitation of localized rotating waves in plasma density cavities by scattering of fast magnetosonic waves
    2004 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 92, no 25 pt.1, p. 255002-Article in journal (Refereed) Published
    Abstract [en]

    An analytic description of electromagnetic waves in an inhomogeneous plasma is applied to investigate excitation of localized rotating waves below the lower hybrid frequency through scattering of fast magnetosonic waves on a density cavity. The magnetosonic wave is focused to left-handed rotating oscillations. We find the amplitude of the localized oscillations, resonance frequencies, and the width of the resonances. The theory is relevant for the lower hybrid solitary structures observed in space plasmas and is shown to be consistent with observations by the Freja satellite.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-91834 (URN)10.1103/PhysRevLett.92.255002 (DOI)15245017 (PubMedID)
    Available from: 2004-05-12 Created: 2004-05-12 Last updated: 2017-12-14Bibliographically approved
    4. Conversion of localized lower hybrid oscillations and fast magnetosonic waves at a plasma density cavity
    Open this publication in new window or tab >>Conversion of localized lower hybrid oscillations and fast magnetosonic waves at a plasma density cavity
    In: Physics of Plasmas, ISSN 1070-664XArticle in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-91835 (URN)
    Available from: 2004-05-12 Created: 2004-05-12Bibliographically approved
    Download full text (pdf)
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  • 335.
    Hall, Jan-Ove
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Eriksson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Leyser, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Excitation of localized rotating waves in plasma density cavities by scattering of fast magnetosonic waves2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 92, no 25 pt.1, p. 255002-Article in journal (Refereed)
    Abstract [en]

    An analytic description of electromagnetic waves in an inhomogeneous plasma is applied to investigate excitation of localized rotating waves below the lower hybrid frequency through scattering of fast magnetosonic waves on a density cavity. The magnetosonic wave is focused to left-handed rotating oscillations. We find the amplitude of the localized oscillations, resonance frequencies, and the width of the resonances. The theory is relevant for the lower hybrid solitary structures observed in space plasmas and is shown to be consistent with observations by the Freja satellite.

  • 336.
    Hall, Jan-Ove
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Leyser, Thomas
    Conversion of trapped upper hybrid oscillations and Z mode at a plasma density irregularity2003In: Physics of Plasmas, ISSN 1070-664X, Vol. 10, no 6, p. 10-Article in journal (Refereed)
  • 337.
    Hamrin, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Andre, M
    Ganguli, G
    Gavrishchaka, VV
    Koepke, ME
    Zintl, MW
    Ivchenko, N
    Karlsson, T
    Clemmons, JH
    Inhomogeneous transverse electric fields and wave generation in the auroral region: A statistical study2001In: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, ISSN 0148-0227, Vol. 106, no A6, p. 10803-10816Article in journal (Refereed)
    Abstract [en]

    We use data from the Freja satellite to investigate the importance of localized transverse DC electric fields for the generation of broadband waves responsible for ion heating in the auroral region. Theoretical models indicate that shear in the plasma Row

  • 338.
    Hamrin, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Andre, M
    Department of Physics and Astronomy.
    Norqvist, P
    Ronnmark, K
    The importance of a dark ionosphere for ion heating and auroral arc formation.2000In: Geophysical-Research-Letters, Vol. 27, no 11, p. 1635-1638Article in journal (Refereed)
    Abstract [en]

    The authors present observations from the Freja Satellite to show that density reductions and ion heating at Freja heights are anticorrelated with solar illumination of the ionosphere. When the ionospheric foot-point of a flux-tube is in shadow, the ambie

  • 339. Harper, G. M.
    et al.
    Brown, A.
    Richter, M. J.
    Holmes, S.
    Ryde, Nils
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Astronomical observatory. Physics, Department of Astronomy and Space Physics.
    TEXES Observations of Betelgeuse: Dynamics and Thermodynamics of the Wind Acceleration Zone2004Conference paper (Other scientific)
  • 340.
    Heiter, Ulrike
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Observational Astronomy. Theoretical Astrophysics.
    Eriksson, Kjell
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Observational Astronomy. Theoretical Astrophysics.
    Geometry of giant star model atmospheres: A consistency test2006In: Astronomy & Astrophysics, Vol. 452, p. 1039-Article in journal (Refereed)
  • 341.
    Heiter, Ulrike
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Observational Astronomy. Theoretical Astrophysics.
    Piskunov, Nikolai
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Observational Astronomy. Theoretical Astrophysics.
    Gustafsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Observational Astronomy. Theoretical Astrophysics.
    Jordi, C.
    Carrasco, J. M.
    Cool stars in the Gaia photometric system2005In: 13th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun, 2005, p. 635-Conference paper (Other scientific)
  • 342.
    Heiter, Ulrike
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Observational Astronomy.
    Smalley, B.
    Stuetz, Ch.
    Kupka, F.
    Kochukhov, Oleg
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Observational Astronomy.
    Eclipsing binaries as a test for synthetic photometry2007In: IAUS 239, Convection in Astrophysics, 2007Conference paper (Other scientific)
  • 343. Helbert, Jörn
    et al.
    Moroz, Ljuba
    Maturili, Alessandro
    Bischoff, Addi
    Warell, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics, Observational Astronomy.
    A set of laboratory analogue materials for the MERTIS instrument on the ESA BepiColombo mission2007In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 40, no 2, p. 272-279Article in journal (Refereed)
    Abstract [en]

    The MERTIS (Mercury Thermal Imaging Spectrometer) instrument on the ESA mission BepiColombo will study the surface of Mercury in the wavelength range from 7 to 14 pin. The analysis of the MERTIS data will be posing a number of significant challenges. To facilitate the development of analytic tools, support planned ground based observations and facilitate a cross calibration with other instruments on BepiColombo and MESSENGER, a list of Mercury analogue materials was compiled. This set of analogue materials is based on our current knowledge of the surface composition of Mercury and includes plagioclase and potassium feldspars, low and high Ca pyroxenes, olivine, elemental sulfur, and as an extraterrestrial analogue a lunar highland soil sample. The samples are prepared in four different grain size separates ranging from 0 to 250 mu m to cover the expected grain size distribution on the surface of Mercury.

  • 344.
    Henriksson, G.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    The grooves on the island of Gotland in the Baltic sea: a neolithic lunar calendar2002In: Astronomy of Ancient Societies, Proceedings from JENAM 2000 & SEAC 2000 in Moscow, Russian Academy of Sciences and Institute of Archaeology, Moscow Nauka , 2002, p. 72-80Conference paper (Refereed)
  • 345.
    Henriksson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    A New Chronology of the Old Babylonian Kingdom and Ur I-III Based on Identification of Solar and Lunar Eclipses2006In: Cosmic Catastrophies, 2006Conference paper (Refereed)
  • 346.
    Henriksson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Chronology for the Egyptian pharaohs of the Amarna period and the Israeli leaders Moses and Joshua by correlation with eight solar eclipses2007In: BAR, British Archaeological Reports International Series: Archaeoastronomy in Archaeology and Ethnography, Papers from the annual meeting of SEAC held in Kecskemét in Hungary in 2004, ISSN 978 1 4073 0081 8, Vol. 1647, p. 133-148Article in journal (Other (popular scientific, debate etc.))
    Abstract [en]

    The periods of rule for Pharaohs during the Amarna period in Egypt is dated by correlation with six solar eclipses at the horizon. Amenhotep IV changed his name to Akhenaten in his sixth year after a powerful solar eclipse during sunrise on 21/6, 1378 BCE, and the decision in his ninth year to build a completely new residential city Akhetaten – The Horizon of the Sun Disk, was taken after the dramatic solar eclipse at the horizon during sunrise on 20/4 1375 BCE. The sudden decision of Tutankhaten to change his name to Tutankhamun in the fourth year and to evacuate Akhetaten, during the winter months of this year, may have been taken after the solar eclipse during sunrise on 14/10, 1356 BCE. An alternative explanation may be a correlation with the extremely bright supernova that appeared in the sky on 9/11, 1355 BCE. This extremely bright supernova may have been interpreted as a second sun in the sky and a contradiction to the new monotheistic adoration of the Sun Disk.

    I identify the solar eclipse in 1258 BCE, which was total in southern Egypt, with the so-called Egyptian darkness mentioned in Exodus as number 9 of the 10 plagues before the people of Israel were given permission to leave Egypt. This eclipse took place in the 46th year of the rule of Ramesses II, 1304-1238 BCE, according to the High Egyptian chronology. The rod that Moses stretched out over the land of Egypt is identified with the long bright tail of comet Encke that dominated the southern sky in January 1258 BCE. The pillar of cloud during the day and pillar of fire during the night, which guided the people of Israel during the exodus from Egypt out in the desert, fits very well with the next bright appearance of comet Encke in May-June 1252 BCE.

    There was another remarkable solar eclipse in 1207 BCE that can be identified as the situation “when the sun was standing still in the valley of Ajalon”, after Joshua’s conquest of the city of Gibeon in Palestine. This date is in good agreement with the results from the modern archaeological excavations in Gibeon. Richard Stephenson has earlier identified this eclipse as taking place in 1131 BCE, but this is too late according to the archaeologists.

  • 347.
    Henriksson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Elements of Greek Astronomy and Religion in Minoan Crete2005In: Current Studies in Archaeoastronomy: Conversations Across Time and Space, Carolina Academic Press, Durham, North Carolina , 2005Chapter in book (Refereed)
  • 348.
    Henriksson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
    Solar Eclipses and Encke´s Comet on Swedish Rock Carvings2005In: Current Studies in Archaeoastronomy: Conversations Across Time and Space, Carolina Academic Press, Durham, North Carolina , 2005Chapter in book (Refereed)
  • 349.
    Henriksson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Department of Physics and Astronomy, Theoretical Astrophysics.
    Some Problems in Minoan Archaeoastronomy2006In: Cosmic Catastrophies, 2006Conference paper (Other (popular scientific, debate etc.))
  • 350.
    Henriksson, Göran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Blomberg, Mary
    Uppsala University.
    The function of the Minoan oval house at Chamaizi2007In: British Archaeological Reports - International series, ISSN 0143-3067, Vol. 1647, p. 15-18Article in journal (Refereed)
    Abstract [en]

    We report the results of our archaeoastronomical investigation of the unique building at Chamaizi in eastern Crete. The structure has been an enigma to Aegean archaeologists because of its oval shape, which is unparalleled in Minoan architecture. Religion has figured prominently in the discussions of the house’s function, primarily due to the discovery of a well and some figurines. We had included it in our pilot study of Minoan astronomical interest since some scholars have categorized it as a peak sanctuary, and these sites are ideally located for astronomical observations. An axial symmetry for the building, however, was impossible to calculate, and this discouraged us to the extent that we left its evaluation to a late stage in our work. When we returned to our data, with the knowledge acquired from our study of a number of other Minoan buildings, we were in a better position to study the house and understand its function. The main entrance was orientated to sunrise on the morning of the winter solstice in the early Middle Minoan period (ca 2000 BCE) and the door on the northern side framed the heliacal setting of Arcturus in the same period.

    The orientation to sunrise at the winter solstice occurs also at the important villa of Vathypetro, and the orientation to Arcturus is the fourth that we have found at Minoan sites. Thus our results from Chamaizi add to the accumulating data that the Minoans consistently oriented important monuments to major celestial events and precisely those events important for maintaining a calendar. A hypothesis that may be made from these results is that the contacts between Minoan sites known from trade can be understood to have included also the intellectual exchange of scientific information resulting in a common calendar and probably also common rituals in connection with it: celebrations of the new year, the beginning and end of the sailing season, and important events in the agricultural year such as ploughing, as we have tried to show in earlier studies.

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