Abstract We present the results of processing three 256-min series of observations of quasi-periodic oscillations of the field of line-of-sight velocities in three sunspots. The Doppler shifts were determined simultaneously for six spectral lines formed at different heights in the solar atmosphere. In addition to the well-known high-frequency (periods of 3–5 min) oscillations, a band of low-frequency oscillations with periods of 60–80 min is revealed in the spectra of the sunspot umbra and magnetic elements located in immediate proximity of the sunspot. Unlike the short-period modes, the power of the long-period mode of line-of-sight velocity oscillations in the sunspot decreases sharply with height: these oscillations are distinctly seen in the line formed at a height of 200 km and almost are not seen in the line with the formation height of 500 km. This is indicative of different physical nature of the short-period and long-period oscillations of a sunspot. If the former are caused by slow magnetosonic waves within the field tube of the spot, the latter are representative of global vertical-radial oscillations of a magnetic element (spot, pore) as a whole near the position of a stable equilibrium.


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    Titel :

    Vertical distribution of the power of short- and long-period oscillations in a sunspot and in surrounding magnetic elements


    Beteiligte:
    Efremov, V. I. (Autor:in) / Parfinenko, L. D. (Autor:in) / Soloviev, A. A. (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    2009




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch


    Schlagwörter :

    Klassifikation :

    BKL:    55.60 Raumfahrttechnik / 39.00 Astronomie: Allgemeines / 50.93 Weltraumforschung
    Lokalklassifikation TIB:    770/3520/8000




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