MHD Wave in Sunspots

Сыч, Р. А.

doi:10.1002/9781119055006.ch27

Cited by 12 publications

(6 citation statements)

References 104 publications

(190 reference statements)

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“…We found a compact pulsating source near the centre of the umbra, where spherical waves begin to propagate. This source is highlighted in figures 2 e and 3 (00:12:57 UT) as a circle and is accompanied by the modulation of the approximately 3-min oscillations, visible as low-frequency wave trains with approximately 10−20 min periodicities [46]. During the development of the wave trains, wavefront shape transformations occur, depending on the specific direction of motion.…”

Section: Resultsmentioning

confidence: 99%

The dynamics of 3-min wavefronts and their relation to sunspot magnetic fields

Сыч

Jess

2020

Phil. Trans. R. Soc. A.

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We present a study of wave processes occurring in solar active region NOAA 11131 on 10 December 2010, captured by the Solar Dynamics Observatory in the 1600 Å, 304 Å and 171 Å channels. For spectral analysis, we employed pixelized wavelet filtering together with a developed digital technique based on empirical mode decomposition. We studied the ∼3-minute wave dynamics to obtain relationships with the magnetic structuring of the underlying sunspot. We found that during development of wave trains the motion path occurred along a preferential direction, and that the broadband wavefronts can be represented as a set of separate narrowband oscillation sources. These sources become visible as the waves pass through the umbral inhomogeneities caused by the differing magnetic field inclination angles. We found the spatial and frequency fragmentation of wavefronts, and deduced that the combination of narrowband spherical and linear parts of the wavefronts provide the observed spirality. Maps of the magnetic field inclination angles confirm this assumption. We detect the activation of umbral structures as the increasing of oscillations in the sources along the front ridge. Their temporal dynamics are associated with the occurrence of umbral flashes. Spatial localization of the sources is stable over time and depends on the oscillation period. We propose that these sources are the result of wave paths along the loops extending outwards from the magnetic bundles of the umbra. This article is part of the Theo Murphy meeting issue ‘High-resolution wave dynamics in the lower solar atmosphere’.

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Section: Resultsmentioning

confidence: 99%

The dynamics of 3-min wavefronts and their relation to sunspot magnetic fields

Сыч

Jess

2020

Phil. Trans. R. Soc. A.

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“…Different features observed over sunspots at different atmospheric heights host a variety of waves, such as the 5-min photospheric oscillations, the 3-min chromospheric oscillations, umbral flashes and waves, running penumbral waves, and propagating coronal waves (see for e.g., reviews by Bogdan & Judge 2006;De Moortel & Nakariakov 2012;Sych 2016). Although these oscillations and waves have been studied for decades, we are still far from understanding the physics behind their origin and the possible coupling among them.…”

Section: Introductionmentioning

confidence: 99%

“…Although these oscillations and waves have been studied for decades, we are still far from understanding the physics behind their origin and the possible coupling among them. It has further been suggested that sunspot waves and oscillations may play an important role in the initiation of solar flares and coronal mass ejections (CMEs), as well as solar wind acceleration (see, e.g., Sych 2016). Recent studies show that sunspot waves may also play an important role in the triggering of coronal jets (Chandra et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Direct Observations of Different Sunspot Waves Influenced by Umbral Flashes

Sharma

Gupta

Tripathi

et al. 2017

ApJ

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We report the simultaneous presence of chromospheric umbral flashes and associated umbral waves, and propagating coronal disturbances, in a sunspot and related active region. We have analyzed time-distance maps obtained using the observations from Atmospheric Imaging Assembly (AIA) on-board Solar Dynamics Observatory (SDO). These maps show the simultaneous occurrence of different sunspot oscillation and waves such as umbral flashes, umbral waves, and coronal waves. Analysis of the original light curves, i.e., without implementing any Fourier filtering on them, show that the amplitudes of different sunspot waves observed at different atmospheric layers change in synchronization with the light curves obtained from the umbral flash region, thus demonstrating that these oscillations are modulated by umbral flashes. This study provides the first observational evidence of the influence of sunspot oscillations within the umbra on other sunspot waves extending up to the corona. The properties of these waves and oscillations can be utilized to study the inherent magnetic coupling among different layers of the solar atmosphere above sunspots.

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“…It has been observed that the sunspots mostly occur in solar active regions and more sunspots are observed during the periods of increased magnetic activity. They are the source of various kind of oscillations (e.g., see [53], [54] and citations therein) and can be linked to other solar dynamical processes. Sych et.…”

Section: Sunspotsmentioning

confidence: 99%

Solar Dynamical Processes I

Mishra

Kumar

2018

Adv. J. Grad. Res.

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The article gives a concise overview of solar dynamical processes and their impacts on the space weather. This article is based on the observational and theoretical developments made during last few decades. The article begins with a brief discussion of the Sun and the solar interior, from the core to the solar corona. We discuss the solar magnetic field and provide some basic understanding of the solar dynamo model. The solar dynamical processes, the transient as well as the gradual, are the manifestations of the Sun’s magnetic field. Magnetic reconnection, as well as submergence and emergence of magnetic flux tubes, plays an important role in the solar activities. This article tries to cover a range of dynamical processes, including sunspots, solar prominences and bright points. We also discussed various models of the dynamical processes along with their properties and effect on other activities occurring on the Sun.

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MHD Wave in Sunspots

Cited by 12 publications

References 104 publications

The dynamics of 3-min wavefronts and their relation to sunspot magnetic fields

The dynamics of 3-min wavefronts and their relation to sunspot magnetic fields

Direct Observations of Different Sunspot Waves Influenced by Umbral Flashes

Solar Dynamical Processes I

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