Seismic Transients from Flares in Solar Cycle 23

Donea, Alina-Catalina

doi:10.1007/s11214-011-9787-7

Cited by 33 publications

(41 citation statements)

References 56 publications

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“…The stacked nature of egression kernels presented in Figure 1(a), is very similar to the measurements obtained for other quakes (Donea, Braun, and Lindsey, 1999;Donea and Lindsey, 2005;Donea, 2011). In these works the authors suggest that this could be the result of interference caused by the rapid motion of the source, roughly in the direction along which the kernels are stacked.…”

Section: Discussionsupporting

confidence: 82%

“…Considerable anisotropy in the acoustic amplitude of the ripples from the vantage of the sources has been observed for most quakes (Kosovichev, 2006;Moradi, Donea, Lindsey et al, 2007;Donea, 2011). In fact, Donea (2011) suggests that the maximum amplitude of the ripples emanating from a moving source is generally along the axis of the source, displaced from the source location in the direction of the motion.…”

Section: Discussionmentioning

confidence: 99%

“…In fact, Donea (2011) suggests that the maximum amplitude of the ripples emanating from a moving source is generally along the axis of the source, displaced from the source location in the direction of the motion. This is confirmed for both of our sources by our directional time-distance diagrams (see Figures 2 and 3, where after considering various arcs, the results where the time-distance ridge appears the strongest are presented).…”

Section: Discussionmentioning

confidence: 99%

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Properties of the 15 February 2011 Flare Seismic Sources

et al. 2012

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The first near-side X-class flare of the Solar Cycle 24 occurred in February 2011 and produced a very strong seismic response in the photosphere. One sunquake was reported by Kosovichev (2011) followed by the discovery of a second sunquake by Zharkov et al (2011). The flare had a two-ribbon structure and was associated with a flux rope eruption and a halo coronal mass ejection (CME) as reported in the CACTus catalogue. Following the discovery of the second sunquake and the spatial association of both sources with the locations of the feet of the erupting flux rope (Zharkov et al 2011) we present here a more detailed analysis of the observed photospheric changes in and around the seismic sources. These sunquakes are quite unusual, taking place early in the impulsive stage of the flare, with the seismic sources showing little hard X-ray (HXR) emission, and strongest X-ray emission sources located in the flare ribbons. We present a directional time--distance diagram computed for the second source, which clearly shows a ridge corresponding to the travelling acoustic wave packet and find that the quake at the second source happened about 45 seconds to one minute earlier than the first source. Using acoustic holography we report different frequency responses of the two sources. We find strong downflows at both seismic locations and a supersonic horizontal motion at the second site of acoustic wave excitation.Comment: 15 pages, 5 figures, accepted for publication by Solar Physic

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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Properties of the 15 February 2011 Flare Seismic Sources

et al. 2012

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“…Such waves usually propagate as expanding ripples from local impact sources occupying several pixels in the Helioseismic and Magnetic Imager (HMI) Dopplergrams. The cause of these events is a subject of intense debate (e.g., Donea 2011;Kosovichev 2014). Generally, the necessary condition for producing sunquakes is a sudden momentum enhancement in the lower solar atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Energy Release and Initiation of a Sunquake in a C-Class Flare

Sharykin

Kosovichev

Zimovets

2015

ApJ

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We present an analysis of the C7.0 solar flare from 2013 February 17, revealing a strong helioseismic response (sunquake) caused by a compact impact observed with the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory (SDO) in the low atmosphere. This is the weakest known C-class flare generating a sunquake event. To investigate the possible mechanisms of this event and understand the role of accelerated charged particles and photospheric electric currents, we use data from three space observatories: RHESSI, SDO, and Geostationary Operational Environmental Satellite. We find that the photospheric flare impact does not spatially correspond to the strongest hard X-ray emission source, but both of these events are parts of the same energy release. Our analysis reveals a close association of the flare energy release with a rapid increase in the electric currents and suggests that the sunquake initiation is unlikely to be caused by the impact of high-energy electrons, but may be associated with rapid current dissipation or a localized impulsive Lorentz force in the lower layers of the solar atmosphere.

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“…These diagnostics have motivated models in which seismic transients are thermally driven in some instances, by pressure perturbations associated with impulsive heating Kosovichev & Zharkova , 1998;Lindsey & Donea , 2008;Moradi et al , 2007), and by Lorentz-force transients in others, due to the sudden release of magnetic free energy (Hudson, Fisher and Welsch , 2008). For a general review, we refer to Donea (2011).…”

Section: Egression-power Signature Of a Flarementioning

confidence: 99%