Photospheric and Chromospheric Oscillations in Solar Faculae

Кобанов, Н. И.; Pulyaev, V. A.

doi:10.1007/s11207-007-0391-7

Cited by 22 publications

(19 citation statements)

References 19 publications

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“…This dominant period is maintained both through the photosphere and in the low chromosphere. This conclusion is consistent with the previous studies of waves in enhanced network and facular regions (Deubner 1967(Deubner , 1990Howard 1967;Blondel 1971;Woods & Cram 1981;Lites et al 1993;Krijger et al 2001;Centeno et al 2006;Kobanov & Pulyaev 2007;Centeno et al 2009). At all the observed heights, the dominant period of oscillations increases by 15-20% with the magnetic field increasing from 500 to 1500 G. Our results give still more evidence that the long-period waves can propagate with sufficient power to the upper layers in magnetic regions.…”

Section: Discussionsupporting

confidence: 93%

“…Spectral and spectropolarimetric slit observations of waves in plage regions show that the maximum of oscillation power is at frequencies of around 3 mHz (below the temperature minimum cut-off frequency ∼5.2 mHz) both in the photosphere and in the chromosphere (Deubner 1967;Howard 1967;Blondel 1971;Woods & Cram 1981;Lites et al 1993;Centeno et al 2009;Kobanov & Pulyaev 2007;Turova 2011). The dominance of low-frequency oscillations in the chromosphere has also been reported for waves above bright network elements in the quiet Sun (Lites et al 1993;Krijger et al 2001;De Pontieu et al 2003;Bloomfield et al 2006;Tritschler et al 2007;Vecchio et al 2007).…”

Section: Introductionmentioning

confidence: 80%

“…These high-frequency power enhancements are called haloes in the literature on local helioseismic waves. The amplitudes of low-frequency 3 mHz photospheric waves in plages seem to be reduced compared to the quiet Sun by as much as 20-40% (Deubner 1967;Howard 1967;Blondel 1971;Woods & Cram 1981;Kobanov & Pulyaev 2007). A&A 559, A107 (2013) The phase shifts between the velocity oscillations at different heights, φ(V, V), and between the intensity and velocity oscillations at the same height, φ(I, V), have been much less investigated than the power distributions.…”

Section: Introductionmentioning

confidence: 99%

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Properties of oscillatory motions in a facular region

Костик

Khomenko

2013

A&A

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Aims. We study the properties of waves in a facular region of moderate strength in the photosphere and chromosphere. Our aim is to statistically analyse the wave periods, power, and phase relations as a function of the magnetic field strength and inclination. Methods. Our work is based on observations obtained at the German Vacuum Tower Telescope (Observatorio del Teide, Tenerife) using two different instruments: the Triple Etalon SOlar Spectrometer (TESOS) in the Ba ii 4554 Å line to measure velocity and intensity variations through the photosphere and, simultaneously, the Tenerife Infrared Polarimeter (TIP-II), in the Fe i 1.56 μm lines to measure the Stokes parameters and magnetic field strength in the lower photosphere. Additionally, we use the simultaneous broadband filtergrams in the Ca ii H line to obtain information about intensity oscillations in the chromosphere.Results. We find several clear trends in the oscillation behaviour: (i) the period of oscillation increases by 15-20% with the magnetic field increasing from 500 to 1500 G. (ii) The temperature-velocity phase shifts show a strikingly different distribution in the facular region compared to the quiet region, a significant number of cases in the range from −180• to 180• is detected in the facula. (iii) The most powerful chromospheric Ca ii H intensity oscillations are observed at locations with strong magnetic fields (1.3-1.5 kG) inclined by 10-12 degrees, as a result of upward propagating waves with rather low phase speeds, and temperature-velocity phase shifts between 0• and 90• . (iv) The power of the photospheric velocity oscillations from the Ba ii line increases linearly with decreasing magnetic field inclination, reaching its maximum at strong field locations.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

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Properties of oscillatory motions in a facular region

Костик

Khomenko

2013

A&A

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“…Five-minute oscillations attenuated compared to unperturbed areas dominate in the sunspot umbra photosphere (Kobanov 1990), while threeminute ones dominate in the umbra chromosphere (Kobanov et al 2008) and low-frequency (5-35 min) oscillations are localized in the penumbra (Kobanov and Makarchik 2004). In facular regions, five-minute oscillations are observed at both levels (Kobanov and Pulyaev 2007). The solar wind streams, which exert a decisive influence on the Earth's magnetosphere and ionosphere, are known to be associated with coronal holes.…”

Section: Introductionmentioning

confidence: 99%

Periodic variations of the Ba II 4554 Å and Ca II 8542 Å line profiles in coronal holes

2016

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The oscillations of the half-width of the Ba II 4554Å and Ca II 8542Å spectral lines have been analyzed using observations at the base of solar coronal holes (CHs). The observed variations (∼50 mÅ for Ca II and ∼4 mÅ for Ba II) exceed considerably the thermal broadenings of these lines calculated from the measured intensity oscillations, suggesting their nonthermal nature. We point out a number of observational facts that hamper an unambiguous interpretation of the periodic Ba II and Ca II profile variations solely by the manifestation of torsional Alfv´en waves in the lower solar atmosphere.

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“…Although Figure 5 is only for knot 4, this result is typical for all the studied magnetic knots. Earlier, Muglach, Solanki, and Livingston (1995) and Kobanov and Pulyaev (2007) as well registered real oscillations of the magnetic flux in facular regions. Here, the term "real oscillations" implies that the observed oscillations are of the solar origin rather than a result of instrumental artefacts.…”

Section: Oscillations and Fan Structures Above Sunspotsmentioning

confidence: 71%

Influence of the Magnetic Field on Oscillation Spectra in Solar Faculae

2016

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In this work, we studied oscillation parameters in faculae above magnetic knots and in the adjacent to them areas. Using SDO data we analysed oscillations in magnetic strength, Doppler velocity, and intensity signals for the lower photosphere, and in intensity for the higher levels. We found that in the magnetic field strength oscillation spectra in magnetic knots, peaks at a frequency of about 4.8 mHz appear, while there are no such frequencies in the adjacent facular patches of a moderate field strength. On the contrary, Doppler velocity photospheric oscillation spectra are similar for these types of regions: in both cases, the significant peaks are in the 2.5--4.5 mHz range, though the oscillations in magnetic knots are 2--3 times weaker than those at the facular periphery. At the upper photosphere, the dominant frequencies in magnetic knots are 0.5--1 mHz higher than in the medium-field regions. The transition region oscillations above magnetic knots mainly concentrate in the 3--6 mHz range, and those above moderate-field patches concentrate below 3 mHz.Comment: 16 pages, 9 figure

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Photospheric and Chromospheric Oscillations in Solar Faculae

Cited by 22 publications

References 19 publications

Properties of oscillatory motions in a facular region

Properties of oscillatory motions in a facular region

Periodic variations of the Ba II 4554 Å and Ca II 8542 Å line profiles in coronal holes

Influence of the Magnetic Field on Oscillation Spectra in Solar Faculae

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