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  • 1
    Electronic Resource
    Electronic Resource
    Observations of solar oscillations with periods of 160 minutes (1979)
    [s.l.] : Nature Publishing Group
    Nature 277 (1979), S. 635-637 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] At Stanford the relative velocity between a central circular area of radius 0.5/? on the solar disk and most of the remaining area of the solar disk is measured. An optical scheme similar to that described in refs i and 2 is used and is described in detail by Dittmer3. Fig. 1 Superposed epoch ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/277635a0
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  • 2
    Electronic Resource
    Electronic Resource
    Observations of solar pulsations (1976)
    [s.l.] : Nature Publishing Group
    Nature 259 (1976), S. 87-89 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We have modified our solar magnetograph to measure velocities at the solar surface, rather than magnetic fields. Using this apparatus, we have observed fluctuations of period 2 h 40 min, which are remarkably stable. The interpretation of this phenomenon seems to cause much theoretical ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/259087a0
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  • 3
    Electronic Resource
    Electronic Resource
    The Splitting Or Disappearance of the Solar 160-Min Mode? (1997)
    Springer
    Solar physics 176 (1997), S. 45-57 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ‘CrAO-WSO’-network experiment was designed for detection of low-degree oscillations of the Sun representing either its normal g -modes or those driven by, e.g., rapid (hypothetical) rotation of the central solar core. The Doppler-shift measurements were made in 1974–1995 at both sites during about 13600 hr, in all. Taking into account the upper limit (≈0.08 m s-1) for amplitudes of potential g-modes, attention is paid to the Sun's behaviour at frequencies near the 9th daily harmonic (period P ≈160. The two main issues follow from analysis of the combined CrAO-WSO data: (a) in 1974–1982 the primary period of solar pulsation was P 0160.0099 ± 0.0016 ± 0.0016 min, but (b) during the last 13 yr it attained a new value, P 1 ≈ 159.9654 ± 0.0010 min, which happens to be a near-annual sidelobe of P 0. We find therefore that the phase stability of the 160-min mode is no longer present: it appears to be splitted at least into a pair of oscillations,P 0 and P 1, having perhaps different physical origins. But the most striking is the fair coincidence of the strongest peaks in the two data sets: CrAO (1974–1995): P = 159.9662 ±0.0006 min, WSO (1977–1994): P = 159.9663 ± 0.0007 min. The existence of two frequencies,P -1 0 and P -1 1, with their separation corresponding to ≈1-yr period, seems to be difficult to explain in terms of gravity g modes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004936013133
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  • 4
    Electronic Resource
    Electronic Resource
    Present state of the study of 160-minutes solar oscillation (1981)
    Springer
    Solar physics 74 (1981), S. 65-71 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Global oscillation of the Sun with a period of 160 rain were first discovered in 1974 and since observed in Crimea during the last 6 years; they were confirmed, in 1976–1979, by Doppler measurements at Stanford (Scherrer et al., 1980) and quite recently by observations of Fossat and Grec at the south geographic pole. The average amplitude of the oscillation is about 0.5 m s-1. The phase shows remarkable stability at the period 160.010 min and good agreement between different sites on the Earth; therefore, this oscillation should now be recognized as definitely of solar origin. It is probably accompanied by synchronous fluctuations in the IR brightness and radio-emission of the Sun, and exhibits a dependence of the amplitude on the phase of solar rotation (with a peak of power at 27.2 days). In agreement with results of the Birmingham group and the South Pole observation we also find evidence in favour of a discrete spectrum within the 5 min global oscillations of the Sun, with the average splitting of about 69.5 μHz in frequency. Strict gas-dynamical equations being solved in the adiabatic approximation for a polytropic sphere n = 3 display the pattern of radial oscillations with wave packets separated by 120 m time-intervals filled with high frequency (and split by 117 μHz) oscillations implying a similarity with the observed pattern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151275
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  • 5
    Electronic Resource
    Electronic Resource
    Étude de la localisation des éruptions dans la structure magnétique évolutive des régions actives solaires (1968)
    Springer
    Solar physics 5 (1968), S. 187-206 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Summary A study of the localization of flares in the evolving magnetic pattern of solar Active Regions. From the material of exceptional completeness collected for the ‘Cooperative Study of Solar Active Regions’, we attempt to define the spatio-temporal conditions of flare occurrence inside the evolving magnetic structure of Active Regions. To describe the evolution of the magnetic pattern of an A.R. we introduce the concept of ‘evolving magnetic feature’ (SME, from the French equivalent ‘Structure magnétique évolutive’): it is a patch of field of a given polarity, generally bound by a closed ‘isogauss’ of longitudinal field, which appears, evolves, and disappears during the life of the A.R. These SME have characteristic sizes of 104–105 km and may contain sunspots or not. We establish the following laws: (1) flares at their beginning are localized on two (or more) SME of opposite polarities; this result was already known. (2) of the two Sme of opposite polarities which take part in the flare, one is increasing, the other decreasing in area (and magnetic flux). With the help of these laws it was possible to predict the spatio-temporal location of the majority of flares occurring in a large A.R. observed during September 1965.
    Notes: Résumé A l'aide d'un matériel d'observation exceptionnellement complet réuni dans le cadre de la ‘Cooperative Study of Solar Active Regions’, nous avons tenté de préciser les conditions spatiotemporelles de l'occurrence des éruptions dans la structure magnétique évolutive des Régions Actives. Pour décrire l'évolution de la configuration magnétique des R.A., nous introduisons le concept de ‘structure magnétique évolutive’ (SME.): il s'agit d'une petite zone de polarité magnétique donnée, généralement limitée par une ‘sogauss’ fermée du champ longitudinal, qui apparaît, évolue et disparaît au cours de la vie de la R.A. Les SME ont des dimensions caractéristiques de 104–105 km et peuvent contenir ou non des taches. On établit les lois suivantes: (1) les éruptions à leur début sont localisées sur deux SME (ou plusieurs) de polarités opposées, résultat déjà connu. (2) des deux SME de polarités opposées intervenant dans une éruption, l'une est d'aire (ou flux magnétique) croissante, l'autre décroissante. A l'aide de ces deux lois on a pu prédire la localisation spatio-temporelle de la majorité des éruptions contenues dans une R.A. observée en septembre 1965.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00147965
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  • 6
    Electronic Resource
    Electronic Resource
    Power spectrum of long-period solar oscillations and 160-min pulsations during 1974–82 (1984)
    [s.l.] : Nature Publishing Group
    Nature 307 (1984), S. 247-249 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The Crimean solar magnetograph with a special Doppler shift modification4 is being used continuously to measure the wavelength difference between two profiles of the same nonmagnetic spectral line ? 5,124 -one from the central circular area (0.66?) of the solar disk, and the other from the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/307247a0
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  • 7
    Electronic Resource
    Electronic Resource
    The first results of solar observations made in the Crimean Astrophysical Observatory using a magneto-optical filter (1996)
    Springer
    Radiophysics and quantum electronics 39 (1996), S. 916-920 
    Details
    ISSN: 1573-9120
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The results of observations of Doppler velocities and solar magnetic fields using a magneto- optical filter (MOF) are presented. The MOF-based instrument was manufactured and supplied to the Crimean Astrophysical Observatory (CrAO) by the University of Southern California. It is one of three similar instruments designed to establish the helioseismology network „Mount Wilson —CrAO — AFiF” (Fesenkov Astrophysical Institute in Alma- Ata.) Apart from its main purpose — obtaining a long time series of the Doppler velocity measurements to study the internal solar structure and recording the magnetic fields for the ground- based support of the SOHO project — the instrument allows us to study different structural formations in the solar atmosphere in Na D1 and D2 spectral lines. This conclusion relies on the comparison between the magnetic field and beam velocity maps calculated using the filtergram pairs, which were recorded twice a minute by 512×512 video-camera (1024×1024 camera will be used in the future studies).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02250963
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  • 8
    Electronic Resource
    Electronic Resource
    The comparison of the magnetographic magnetic field measured in different spectral lines (1973)
    Springer
    Solar physics 31 (1973), S. 307-316 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The discrepancies in the values of longitudinal magnetic field obtained from magnetographic records in different spectral lines are considered. On the basis of extensive data including 60 pairs of magnetographic maps for 11 spectral lines, obtained simultaneously for one of these lines and λ6103 with the aid of the Crimean double channel magnetograph, the following conclusions have been reached. The relative field strength $$\delta (\lambda i) = {{H\parallel (\lambda _i )} \mathord{\left/ {\vphantom {{H\parallel (\lambda _i )} {H\parallel }}} \right. \kern-\nulldelimiterspace} {H\parallel }}$$ (6103) depends partly on the distance from the center of the disk (Figure 4) and mainly on the magnetic sensitivity of the line gλ2 (Figure 3), pointing to the primary role of saturation effect. The possible influence of line asymmetry on these discrepancies is also suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152808
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  • 9
    Electronic Resource
    Electronic Resource
    Manifestation of the 160-min solar oscillations in velocity and brightness (optical and radio observations) (1983)
    Springer
    Solar physics 82 (1983), S. 9-19 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract All evidence of the solar origin of 160-min period oscillations is collected, and the present state of observations of this oscillation in optical and radio-ranges is considered. The main results are summarized: (a) the 160-min oscillation was observed in 1981 as well as before, (b) an attempt to find a nonradial component with l = 2 has failed, (c) the intensity and circular polarization of radioemission show with statistical significance the presence of this 160-min periodicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00145541
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  • 10
    Electronic Resource
    Electronic Resource
    160 minute solar variations and the 22 year cycle (1990)
    Springer
    Solar physics 128 (1990), S. 269-280 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Systematic measurements of the differential Doppler velocity of the Sun have been performed in Crimea from 1974 through 1988 (total 987 days, 6197 hours of observations). They confirm the presence of a long-term phase-coherent solar pulsation with a period of 160.010 min. On the other hand, the analysis of new data suggests that solar 160 min pulsation might, in frequency, have a multiplet fine structure. In particular, large changes of amplitude and phase of the pulsation over the years 1982–1986 may indicate that during the last few years we have been observing the solar 160 min oscillation of the ‘second portion’ of the 22 year solar cycle. It is further noted that the beat period of the two closely spaced frequencies (periods are 160.0101 and 160.0126 min) equals 19.5 ± 1.1 year, which is in good agreement with the average length of the solar magnetic activity cycle, 20–22 years. Being verified, this unpredicted property of the pulsation can offer a novel possibility for probing the Sun's interior and perhaps for the study of the internal rotation and 11(22) year cycle of a star.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00154163
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