ANATOMY OF A SOLAR FLARE: MEASUREMENTS OF THE 2006 DECEMBER 14 X-CLASS FLARE WITH GONG,HINODE, ANDRHESSI

Abstract

Some of the most challenging observations to explain in the context of existing flare models are those related to the lower atmosphere and below the solar surface. Such observations, including changes in the photospheric magnetic field and seismic emission, indicate the poorly understood connections between energy release in the corona and its impact in the photosphere and the solar interior. Using data from Hinode, TRACE, RHESSI, and GONG we study the temporal and spatial evolution of the 2006 December 14 X-class flare in the chromosphere, photosphere, and the solar interior. We investigate the connections between the emission at various atmospheric depths, including acoustic signatures obtained by time-distance and holography methods from the GONG data. We report the horizontal displacements observed in the photosphere linked to the timing and locations of the acoustic signatures we believe to be associated with this flare, their vertical and horizontal displacement velocities, and their potential implications for current models of flare dynamics.

Properties of the 15 February 2011 Flare Seismic Sources

“…Similar plots of photospheric variations where the data were averaged over the egression sources have also been presented in Figure 4 of Zharkov, Green, Matthews et al (2011). We note the difference between the two figures in the magnetic-field and intensity responses.…”

“…In this work, the egression power is computed for each integral frequency from 3 to 10 mHz, by applying 2-mHz frequency bandwidth filters to the data (for acoustic energy estimates in Section 3 we use the same egression computation but with 1-mHz frequency bandwidth) and using Green functions built for surface monochromatic point source of corresponding frequency using geometrical optics approach (Donea, Braun, and Lindsey, 1999;Donea, Lindsey, and Braun, 2000;Lindsey and Braun, 2000;Matthews, Zharkov, and Zharkova, 2011;Zharkov, Green, Matthews et al, 2011;. The pupil size is set from 10 to 40 Megameters.…”

“…without convective motions, then these waves will be observed as accelerating ripples on the surface, contracted to a ridge in a timedistance diagram computed at the source, and seen as a bright emission around the source time and location in an egression power map. The holographic method is more sensitive, but vulnerable to noise, variations from the assumed model and is susceptible to an increased possibility of false detections, which is normally handled by analysing the statistical significance of the detected signal (Donea, Lindsey, and Braun, 2000;Donea and Lindsey, 2005;Matthews, Zharkov, and Zharkova, 2011). …”

“…Using acoustic holography Zharkov, Green, Matthews et al (2011) have shown that a second, apparently weaker, source of acoustic waves is present and have shown that the sunquakes occurred at the foot-points of a flux rope. The presence and location of the flux rope has been deduced based on a straight-forward observational case, making use of the photospheric magnetic flux distribution, sigmoidal structure,…”

Spectroscopic Signatures Related to a Sunquake

“…This observed correlation has led to suggestions that chromospheric shocks, which arise as the result of the pressure transients driven by the hydrodynamic response of the ambient plasma to the precipitation of energetic particles into the chromosphere; pressure transients that are related to back-warming of the photosphere by enhanced chromospheric radiation, (e.g., Donea & Lindsey 2005); and Lorentz force transients that occur while the coronal field is being reconfigured (e.g., Hudson et al 2012), may be potential drivers of the acoustic emission. However, the launch of the Solar Dynamics Observatory (SDO), coupled with now finely honed detection techniques (Zharkov et al 2011b), has led to a series of SQ observations that show significantly weaker correlations between the location of the acoustic sources and the areas of strongest particle precipitation and enhanced whitelight emission, as well as a hitherto undiscovered connection to the ends of the erupting flux rope (Matthews et al 2011;Zharkov et al 2011aZharkov et al , 2013aZharkov et al , 2013bPedram & Matthews 2012), suggesting that we are still a long way from understanding the mechanism(s) responsible for producing these important events. Indeed, recent work by Judge et al (2014) reports unique and important observations in the infrared during an SQ that constrains the depth of the flare heating to be in the photosphere (100 ± 100 km), but also demonstrates that the level of non-magnetic and magnetic energy fluxes consistent with their observations are too low to drive the acoustic transient.…”