Sunquake Generation by Coronal Magnetic Restructuring

Russell, A. J. B.; Mooney, Michaela; Leake, J. E.; Hudson, H. S.

doi:10.3847/0004-637x/831/1/42

Cited by 19 publications

(8 citation statements)

References 35 publications

(70 reference statements)

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“…The location, strength, and timing of the sources can now be compared with the magnetic evolution. Predictions from theoretical and numerical studies (e.g., Lindsey et al 2014;Russell et al 2016) regarding the role of specific magnetic configuration can also be tested.…”

Section: Discussion and Outlookmentioning

confidence: 99%

Investigating the Magnetic Imprints of Major Solar Eruptions with SDO/HMI High-cadence Vector Magnetograms

Sun

Hoeksema

Liu

et al. 2017

ApJ

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The solar active region photospheric magnetic field evolves rapidly during major eruptive events, suggesting appreciable feedback from the corona. Previous studies of these "magnetic imprints" are mostly based on lineof-sight only or lower-cadence vector observations; a temporally resolved depiction of the vector field evolution is hitherto lacking. Here, we introduce the high-cadence (90 s or 135 s) vector magnetogram dataset from the Helioseismic and Magnetic Imager (HMI), which is well suited for investigating the phenomenon. These observations allow quantitative characterization of the permanent, step-like changes that are most pronounced in the horizontal field component (B h ). A highly structured pattern emerges from analysis of an archetypical event, SOL2011-02-15T01:56, where B h near the main polarity inversion line increases significantly during the earlier phase of the associated flare with a time scale of several minutes, while B h in the periphery decreases at later times with smaller magnitudes and a slightly longer time scale. The dataset also allows effective identification of the "magnetic transient" artifact, where enhanced flare emission alters the Stokes profiles and the inferred magnetic field becomes unreliable. Our results provide insights on the momentum processes in solar eruptions. The dataset may also be useful to the study of sunquakes and data-driven modeling of the corona.

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Section: Discussion and Outlookmentioning

confidence: 99%

Investigating the Magnetic Imprints of Major Solar Eruptions with SDO/HMI High-cadence Vector Magnetograms

Sun

Hoeksema

Liu

et al. 2017

ApJ

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“…a hydrodynamic impact) causing the seismic response (Kosovichev and Zharkova 1998;Kosovichev 2014b;Zharkova and Zharkov 2015). Donea (2011) details several alternative generation mechanisms for sunquakes that have been proposed, including a generation mechanism based on the direct interaction of highenergy particles (electrons or protons) with the photosphere (Donea and Lindsey 2005;Zharkova and Zharkov 2007); pressure transients related to photospheric backwarming by enhanced chromospheric radiation (Lindsey and Braun 2000;Donea and Lindsey 2005); flare acoustic emission due to impulsive heating of the low photosphere and radiative backwarming (Donea et al 2006); and a magnetic jerk that manifests as a seismic response occurring during the re-organisation of the magnetic topology, specifically a change in field line inclination at the footpoints , and see recent extension by Russell et al 2016). Donea (2011) reports that (with current instruments) sunquakes are a rare phenomenon and most flares do not generate detectable seismic emission in the p-mode spectrum.…”

Section: Future Directions and Key Unanswered Questionsmentioning

confidence: 99%

Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares

et al. 2018

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Solar flare emission is detected in all EM bands and variations in flux density of solar energetic particles. Often the EM radiation generated in solar and stellar flares shows a pronounced oscillatory pattern, with characteristic periods ranging from a fraction of a second to several minutes. These oscillations are referred to as quasi-periodic pulsations (QPPs), to emphasise that they often contain apparent amplitude and period modulation. We review the current understanding of quasi-periodic pulsations in solar and stellar flares. In particular, we focus on the possible physical mechanisms, with an emphasis on the underlying physics that generates the resultant range of periodicities. These physical mechanisms include MHD oscillations, self-oscillatory mechanisms, oscillatory reconnection/reconnection reversal, wave-driven reconnection, two loop coalescence, MHD flow over-stability, the equivalent LCR-contour mechanism, and thermal-dynamical cycles. We also provide a histogram of all QPP events published in the literature at this time. The occurrence of QPPs puts additional constraints on the interpretation and understanding of the fundamental processes operating in flares, e.g. magnetic energy liberation and particle acceleration. Therefore, a full understanding of QPPs is essential in order to work towards an integrated model of solar and stellar flares.

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“…These models can explain seismic events where HXR or white light (WL) emission is detected and provide an explanation for SQ generation. One of the issues with these interpretations is that the shock front which propagates in the solar interior can experience significant damping, depleting the energy of the seismic wave (Russell et al 2016). Furthermore, the source of the SQ is sometimes detected away from the site of the HXR emission (Zharkov et al 2011).…”

Section: Introductionmentioning

confidence: 99%

The Chromospheric Response to the Sunquake Generated by the X9.3 Flare of NOAA 12673

Quinn¹,

Reid²,

Mathioudakis³

et al. 2019

ApJ

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Active region NOAA 12673 was extremely volatile in 2017 September, producing many solar flares, including the largest of solar cycle 24, an X9.3 flare of 06 September 2017. It has been reported that this flare produced a number of sunquakes along the flare ribbon (Sharykin & Kosovichev 2018;Zhao & Chen 2018). We have used co-temporal and co-spatial Helioseismic and Magnetic Imager (HMI) line-of-sight (LOS) and Swedish 1-m Solar Telescope observations to show evidence of the chromospheric response to these sunquakes. Analysis of the Ca II 8542Å line profiles of the wavefronts revealed that the crests produced a strong blue asymmetry, whereas the troughs produced at most a very slight red asymmetry. We used the combined HMI, SST datasets to create time-distance diagrams and derive the apparent transverse velocity and acceleration of the response. These velocities ranged from 4.5 km s −1 to 29.5 km s −1 with a constant acceleration of 8.6 x 10 −3 km s −2 . We employed NICOLE inversions, in addition to the Center-of-Gravity (COG) method to derive LOS velocities ranging 2.4 km s −1 to 3.2 km s −1 . Both techniques show that the crests are created by upflows. We believe that this is the first chromospheric signature of a flare induced sunquake.

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Sunquake Generation by Coronal Magnetic Restructuring

Cited by 19 publications

References 35 publications

Investigating the Magnetic Imprints of Major Solar Eruptions with SDO/HMI High-cadence Vector Magnetograms

Investigating the Magnetic Imprints of Major Solar Eruptions with SDO/HMI High-cadence Vector Magnetograms

Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares

The Chromospheric Response to the Sunquake Generated by the X9.3 Flare of NOAA 12673

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