Spectroscopic Signatures Related to a Sunquake

Abstract

The presence of flare related acoustic emission (sunquakes) in some flares represents a severe challenge to our current understanding of flare energy transport processes. We present a comparison of new spectral observations from Hinode's EUV imaging Spectrometer (EIS) and the Interface Region Imaging Spectrograph (IRIS) of the atmosphere above a sunquake, and compare them to the spectra observed in a part of the flaring region with no acoustic signature. Evidence for the sunquake is determined using both time-distance and acoustic holography methods, and we find that, unlike many previous sunquake detections, the signal is rather dispersed, but that the time-distance and 6 and 7 mHz sources converge at the same spatial location. We also see some evidence for different evolution at different frequencies, with an earlier peak at 7 mHz than at 6 mHz. Using spectroscopic measurements we find that in this location at the time of the 7 mHz peak the spectral emission is significantly more intense, shows larger velocity shifts and substantially broader profiles than in the location with no sunquake, and that there is a good correlation between blue-shifted, hot coronal, hard X-ray (HXR) and red-shifted chromospheric emission, consistent with the idea of a strong downward motion driven by rapid heating by non-thermal electrons and the formation of chromospheric shocks. Exploiting the diagnostic potential of the Mg II triplet lines, we also find evidence for a single, large temperature increase deep in the atmosphere, consistent with this scenario. The time of the 6 mHz and time-distance peak signal coincides with a secondary peak in the energy release process, but in this case we find no evidence of HXR emission in the quake location, but very broad spectral lines, strongly shifted to the red, indicating the possible presence of a significant flux of downward propagating Alfven waves.

arXiv comment39 pages, 13 figures, accepted for publication in ApJ

References in corpus (10)

• The Interface Region Imaging Spectrograph (IRIS)
• The Formation of IRIS diagnostics. IV. The Mg II triplet lines as a new diagnostic for lower chromospheric heating
• On the origin of 3 seismic sources in the proton-rich flare of October 28, 2003
• February 15, 2011: sun-quakes produced by flux rope eruption
• The fast filament eruption leading to the X-flare on March 29, 2014
• On the Origin of a Sunquake during the 29 March 2014 X1 Flare
• Magneto--Acoustic Energetics Study of the Seismically Active Flare of 15 February 2011
• Comparison of seismic signatures of flares obtained by SOHO/MDI and GONG instruments
• Transient artifacts in a flare observed by the Helioseismic and Magnetic Imager on the Solar Dynamics Observatory
• On the Seismicity of September 7, 2011 X1.8-class Flare

Cited by in corpus (17)

• Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares
• The Atmospheric Response to High Nonthermal Electron Beam Fluxes in Solar Flares I: Modeling the Brightest NUV Footpoints in the X1 Solar Flare of 2014 March 29
• A decade of H$\alpha$ transits for HD 189733 b: stellar activity versus absorption in the extended atmosphere
• Non-Gaussian Velocity Distributions in Solar Flares from Extreme Ultraviolet Lines: A Possible Diagnostic of Ion Acceleration
• Observations and Modelling of the Pre-Flare Period of the 29 March 2014 X1 Flare
• The CARMENES search for exoplanets around M dwarfs: Wing asymmetries of H$\alpha$, Na I D, and He I lines
• Sunquake Generation by Coronal Magnetic Restructuring
• The Triggering of the 29-March-2014 Filament Eruption
• Forward modelling of particle acceleration and transport in an individual solar flare
• The Chromospheric Response to the Sunquake generated by the X9.3 Flare of NOAA 12673
• The 17 February 2013 sunquake in the context of the active region's magnetic field configuration
• Mysterious anomalies in Earth's atmosphere and strongly interacting Dark Matter
• WASP-12b: A Mass-Losing Extremely Hot Jupiter
• A Possible Selection Rule for Flares Causing Sunquakes
• The CARMENES search for exoplanets around M dwarfs. Variability of the He I line at 10830 Å
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)
• Flare Induced Sunquake Signatures in the Ultraviolet as Observed by the Atmospheric Imaging Assembly