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Sun, Ming-Tsung; Chou, Dean‐Yi

doi:10.1023/a:1020909524039

Cited by 13 publications

(3 citation statements)

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“…There is considerable observational evidence that sunspots have large effects on the amplitude of solar p-modes as measured by Doppler velocity. Measuring the power of an annular region surrounding a sunspot Braun et al (1987) found that sunspots (Couvidat et al, 2006), the dotted curve is derived by applying the technique of acoustic imaging (Sun et al, 2002); (B) solid and dashed curves are from Bogart et al (2008) and dot-dashed curve is from Gizon et al (2009); both the curves are derived through the ring-diagram method. Figure from Kosovichev (2012).…”

Section: Power Absorption and Acoustic Emissionsmentioning

confidence: 99%

“…FIGURE 2Sound speed beneath various sunspots obtained by different local helioseismology methods: (A) solid, dashed, and dot-dashed curves are obtained by using time-distance helioseismology technique(Couvidat et al, 2006), the dotted curve is derived by applying the technique of acoustic imaging(Sun et al, 2002); (B) solid and dashed curves are fromBogart et al (2008) and dot-dashed curve is fromGizon et al (2009); both the curves are derived through the ring-diagram method. Figure fromKosovichev (2012).…”

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confidence: 99%

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Seismology of active regions: Current status and perspectives

Tripathy

2023

Front. Astron. Space Sci.

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The goal of helioseismology is to provide accurate information about the Sun’s interior from the observations of the wave field at its surface. In the last three decades, both global and local helioseismology studies have made significant advances and breakthroughs in solar physics. However, 3-d mapping of the structure and dynamics of sunspots and active regions below the surface has been a challenging task and is among the long standing and intriguing puzzles in solar physics due to the complexity of the turbulent and dynamic nature of magnetized regions. In this review, I present some of the recent results relevant for helioseismology of sunspots and active regions obtained from high resolution observations, forward modeling and numerical simulations.

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Section: Power Absorption and Acoustic Emissionsmentioning

confidence: 99%

mentioning

confidence: 99%

Seismology of active regions: Current status and perspectives

Tripathy

2023

Front. Astron. Space Sci.

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“…Local helioseismology techniques, including time-distance helioseismology (Duvall et al, 1993), acoustic imaging (Chang et al, 1997), and helioseismic holography (Lindsey and Braun, 1997), have been widely used to study solar acoustic wave travel times or phase shifts, which are then used to invert interior structures and flow fields beneath sunspots (e.g. Kosovichev, Duvall, and Scherrer, 2000;Gizon, Duvall, and Larsen, 2000;Zhao, Kosovichev, and Duvall, 2001;Sun et al, 2002;Zhao, Kosovichev, and Sekii, 2010). These inversions treated the travel-time shifts as caused by subsurface sound-speed perturbations and plasma flows, and they have provided us the tomographic images of the sunspots' interior properties.…”

Section: Introductionmentioning

confidence: 99%

Toward Waveform Heliotomography: Observing Interactions of Helioseismic Waves with a Sunspot

Zhao¹,

Kosovichev²,

Ilonidis³

2010

Sol Phys

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We investigate how helioseismic waves that originate from effective point sources interact with a sunspot. These waves are reconstructed from observed stochastic wavefields on the Sun by cross-correlating photospheric Doppler-velocity signals. We select the wave sources at different locations relative to the sunspot, and investigate the p-and f -mode waves separately. The results reveal a complicated picture of waveform perturbations caused by the wave interaction with the sunspot. In particular, it is found that for waves originating from outside of the sunspot, p-mode waves travel across the sunspot with a small amplitude reduction and slightly higher speed, and wave amplitude and phase get mostly restored to the quiet-Sun values after passing the sunspot. The f -mode wave experiences some amplitude reduction passing through the sunspot, and the reduced amplitude is not recovered after that. The wave-propagation speed does not change before encountering the sunspot and inside the sunspot, but the wavefront becomes faster than the reference wave after passing through the sunspot. For waves originating from inside the sunspot umbra, both f -and p-mode waves show significant amplitude reductions and faster speed for all propagation paths. A comparison of positive and negative time lags of cross-correlation functions shows an apparent asymmetry in the waveform changes for both the f -and p-mode waves. We suggest that the waveform variations of the helioseismic waves interacting with a sunspot found in this article can be used for developing a method of waveform heliotomography, similar to the waveform tomography of the Earth.

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The Progress of the Taiwan Oscillation Network Project

Sun¹,

Chou²

2003

Advances in Space Environment Research - Volume I

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Untitled

Cited by 13 publications

References 13 publications

Seismology of active regions: Current status and perspectives

Seismology of active regions: Current status and perspectives

Toward Waveform Heliotomography: Observing Interactions of Helioseismic Waves with a Sunspot

The Progress of the Taiwan Oscillation Network Project

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