Space – Time Distribution of G-band and Ca ii H-line Intensity Oscillations in Hinode/SOT – FG Observations

Lawrence, J. K.; Cadavid, A. C.

doi:10.1007/s11207-009-9481-z

Cited by 6 publications

(7 citation statements)

References 28 publications

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“…Lawrence & Cadavid [2010 and Chitta et al [2012a] were able to corroborate these general findings through examination of Hinode/SOT G-band image sequences containing MBPs. However, interestingly Chitta et al [2012a] found evidence to suggest that magnetoacoustic power at the highest temporal frequen-cies (i.e., periodicities less than 100 s) actually demonstrated power amplification.…”

Section: Magneto-acoustic Wavessupporting

confidence: 55%

“…Through examination of the magneto-acoustic wave dynamics associated with large-scale sunspots, Nagashima et al [2007] employed Hinode/SOT observations to reveal how oscillatory power is often drastically reduced in the presence of strong magnetic field concentrations; a common phenomenon now referred to as 'acoustic power suppression' [e.g., Woods & Cram, 1981;Thomas et al, 1982;Title et al, 1992;Parchevsky & Kosovichev, 2007;Chou et al, 2009;Ilonidis & Zhao, 2011;Couvidat, 2013]. Lawrence & Cadavid [2010 and Chitta et al [2012a] were able to corroborate these general findings through examination of Hinode/SOT G-band image sequences containing MBPs. However, interestingly Chitta et al [2012a] found evidence to suggest that magnetoacoustic power at the highest temporal frequen-cies (i.e., periodicities less than 100 s) actually demonstrated power amplification.…”

Section: Magneto-acoustic Wavesmentioning

confidence: 99%

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Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

Jess

Verth

2016

Low‐Frequency Waves in Space Plasmas

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Section: Magneto-acoustic Wavessupporting

confidence: 55%

Section: Magneto-acoustic Wavesmentioning

confidence: 99%

Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

Jess

Verth

2016

Low‐Frequency Waves in Space Plasmas

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“…by Pietarila et al (2009), while the bandwidth of PK-027 data is close to that of the Ca II H high-resolution images, from the SOT/BFI instrument (Tsuneta et al 2008) onboard the Hinode spacecraft, studied e.g. by Lawrence & Cadavid (2010).…”

Section: Discussionmentioning

confidence: 67%

Radiative emission of solar features in the Ca II K line: comparison of measurements and models

Ermolli

Criscuoli

Uitenbroek

et al. 2010

A&A

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Context. The intensity of the Ca II K resonance line observed with spectrographs and Lyot-type filters has long served as a diagnostic of the solar chromosphere. However, the literature contains a relative lack of photometric measurements of solar features observed at this spectral range. Aims. We study the radiative emission of various types of solar features, such as quiet Sun, enhanced network, plage, and bright plage regions, identified on filtergrams taken in the Ca II K line. Methods. We analysed full-disk images obtained with the PSPT, by using three interference filters that sample the Ca II K line with different bandpasses. We studied the dependence of the radiative emission of disk features on the filter bandpass. We also performed a non-local thermal equilibrium (NLTE) spectral synthesis of the Ca II K line integrated over the bandpass of PSPT filters. The synthesis was carried out by utilizing the partial frequency redistribution (PRD) with the most recent set of semi-empirical atmosphere models in the literature and some earlier atmosphere models. As the studied models were computed by assuming the complete redistribution formalism (CRD), we also performed simulations with this approximation for comparison. Results. We measured the center-to-limb variation of intensity values for various solar features identified on PSPT images and compared the results obtained with those derived from the synthesis. We find that CRD calculations derived using the most recent quiet Sun model, on average, reproduce the measured values of the quiet Sun regions slightly more accurately than PRD computations with the same model. This may reflect that the utilized atmospheric model was computed assuming CRD. Calculations with PRD on earlier quiet Sun model atmospheres reproduce measured quantities with a similar accuracy as to that achieved here by applying CRD to the recent model. We also find that the median contrast values measured for most of the identified bright features, disk positions, and filter bandpasses are, on average, a factor ≈1.9 lower than those derived from PRD simulations performed using the recent bright feature models. The discrepancy between measured and modeled values decreases by ≈12% after taking into account straylight effects on PSPT images. When moving towards the limb, PRD computations display closer agreement with the data than performed in CRD. Moreover, PRD computations on either the most recent or the earlier atmosphere models of bright features reproduce measurements from plage and bright plage regions with a similar accuracy.

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“…From their gradient, the corresponding phase velocities are calculated, assuming that the height separation between Ca ii H and G-band is 200 km (see text). power around magnetic concentrations in Ca ii H observations (Lawrence & Cadavid, 2010) shows that the magnetic canopy affects the oscillatory field in this bandpass and, therefore, the latter mechanism may also be in effect as well.…”

Section: Phase Differences Between Ca II H and G-bandmentioning

confidence: 87%

“…lower phase differences. The suppression of acoustic power around magnetic concentrations in Ca ii h observations (Lawrence & Cadavid 2010) shows that the magnetic canopy affects the oscillatory field in this bandpass and, therefore, the latter mechanism may also be in effect as well.…”

Section: Phase Differences Between Ca II H and G-bandmentioning

confidence: 92%

Wave propagation in a solar quiet region and the influence of the magnetic canopy

Kontogiannis

Tsiropoula

Tziotziou

2016

A&A

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Aims. We seek indications or evidence of transmission/conversion of magnetoacoustic waves at the magnetic canopy, as a result of its impact on the properties of the wave field of the photosphere and chromosphere. Methods. We use cross-wavelet analysis to measure phase differences between intensity and Doppler signal oscillations in the Hα, Ca ii h, and G-band. We use the height of the magnetic canopy to create appropriate masks to separate internetwork (IN) and magnetic canopy regions. We study wave propagation and differences between these two regions.Results. The magnetic canopy affects wave propagation by lowering the phase differences of progressive waves and allowing the propagation of waves with frequencies lower than the acoustic cut-off. We also find indications in the Doppler signals of Hα of a response to the acoustic waves at the IN, observed in the Ca ii h line. This response is affected by the presence of the magnetic canopy. Conclusions. Phase difference analysis indicates the existence of a complicated wave field in the quiet Sun, which is composed of a mixture of progressive and standing waves. There are clear imprints of mode conversion and transmission due to the interaction between the p-modes and small-scale magnetic fields of the network and internetwork.

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Space – Time Distribution of G-band and Ca ii H-line Intensity Oscillations in Hinode/SOT – FG Observations

Cited by 6 publications

References 28 publications

Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

Radiative emission of solar features in the Ca II K line: comparison of measurements and models

Wave propagation in a solar quiet region and the influence of the magnetic canopy

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