DETECTING NANOFLARE HEATING EVENTS IN SUBARCSECOND INTER-MOSS LOOPS USING Hi-C

Winebarger, Amy R.; Walsh, R. W.; Moore, Ronald L.; Pontieu, Bart De; Hansteen, V. H.; Cirtain, Jonathan; Golub, L.; Kobayashi, K.; Korreck, K. E.; DeForest, C. E.; Weber, Mark; Title, A. M.; Kuzin, Sergey

doi:10.1088/0004-637x/771/1/21

Cited by 72 publications

(87 citation statements)

References 32 publications

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“…The initial brightening represents a nanoflare that subsequently caused the second brightening through a heating pulse in the loop. This is supported by the results of Winebarger et al (2013), who found that cool dense loops were impulsively heated by nanoflares. …”

Section: Introductionsupporting

confidence: 68%

Forward Modelling of a Brightening Observed by AIA

et al. 2015

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A comprehensive understanding of the different transient events is necessary for any eventual solution of the coronal heating problem. We present a cold loop whose heating caused a short-lived small-scale brightening that was observed by AIA. The loop was simulated using an adaptive hydrodynamic radiation code that considers the ions to be in a state of non-equilibrium. Forward modelling was used to create synthetic AIA intensity plots, which were tested against the observational data to confirm the simulated properties of the event. The hydrodynamic properties of the loop were determined. We found that the energy released by the heating event is within the canonical energy range of a nanoflare.

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Section: Introductionsupporting

confidence: 68%

Forward Modelling of a Brightening Observed by AIA

et al. 2015

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“…Alternatively, energy can propagate downward as energetic particles that can penetrate into the high chromosphere: such particle precipitations are likely more intermittent as they rapidly shift in position. Recent high-resolution observations in the transition region show direct evidence of this type of process (under some magnetic-field conditions) in active regions (Testa et al, 2013;Winebarger et al, 2013). Other recent studies suggest that heating to coronal temperatures may occur primarily in the chromosphere and transition region, as evidenced, e.g.…”

Section: Currents and Reconnectionmentioning

confidence: 88%

The Interface Region Imaging Spectrograph (IRIS)

et al. 2014

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The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33 -0.4 arcsec spatial resolution, two-second temporal resolution, and 1 km s −1 velocity resolution over a field-of-view of up to 175 arcsec × 175 arcsec. . IRIS is sensitive to emission from plasma at temperatures between 5000 K and 10 MK and will advance our understanding of the flow of mass and energy through an interface region, formed by the chromosphere and transition region, between the photosphere and corona. This highly structured and dynamic region not only acts as the conduit of all mass and energy feeding into the corona and solar wind, it also requires an order of magnitude more energy to heat than the corona and solar wind combined. The IRIS investigation includes a strong numerical modeling component based on advanced radiative-MHD codes to facilitate interpretation of observations of this complex region. Approximately eight Gbytes of data (after compression) are acquired by B. De Pontieu (B) ·Harvard-Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138, USA

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“…Not surprisingly, many regions that show strong, transient substructure have already been the subject of analysis, including loops Winebarger et al 2013), dynamics in the moss (Testa et al 2013), evolution in the filament (Alexander et al 2013), and anomalous brightenings (Régnier et al 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Several recent studies have compared the properties of structures observed with Hi-C to the structures observed with the lower-resolution Atmospheric Imaging Array (AIA) on the Solar Dynamics Observatory (SDO; see, for instance, Cirtain et al 2013;Morton & McLaughlin 2013;Testa et al 2013;Winebarger et al 2013;Peter et al 2013;Brooks et al 2013;Alexander et al 2013;Régnier et al 2014). Two of these studies specifically focus on comparing the widths of linear structures, or coronal loops, in Hi-C and AIA data.…”

Section: Introductionmentioning

confidence: 99%

DISCOVERY OF FINELY STRUCTURED DYNAMIC SOLAR CORONA OBSERVED IN THE Hi-C TELESCOPE

Winebarger

Cirtain

Golub

et al. 2014

ApJ

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In the Summer of 2012, the High-resolution Coronal Imager (Hi-C) flew on board a NASA sounding rocket and collected the highest spatial resolution images ever obtained of the solar corona. One of the goals of the Hi-C flight was to characterize the substructure of the solar corona. We therefore examine how the intensity scales from AIA resolution to Hi-C resolution. For each low-resolution pixel, we calculate the standard deviation in the contributing high-resolution pixel intensities and compare that to the expected standard deviation calculated from the noise. If these numbers are approximately equal, the corona can be assumed to be smoothly varying, i.e., have no evidence of substructure in the Hi-C image to within Hi-C's ability to measure it given its throughput and readout noise. A standard deviation much larger than the noise value indicates the presence of substructure. We calculate these values for each low-resolution pixel for each frame of the Hi-C data. On average, 70% of the pixels in each Hi-C image show no evidence of substructure. The locations where substructure is prevalent is in the moss regions and in regions of sheared magnetic field. We also find that the level of substructure varies significantly over the roughly 160 s of the Hi-C data analyzed here. This result indicates that the finely structured corona is concentrated in regions of heating and is highly time dependent.

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DETECTING NANOFLARE HEATING EVENTS IN SUBARCSECOND INTER-MOSS LOOPS USING Hi-C

Cited by 72 publications

References 32 publications

Forward Modelling of a Brightening Observed by AIA

Forward Modelling of a Brightening Observed by AIA

The Interface Region Imaging Spectrograph (IRIS)

DISCOVERY OF FINELY STRUCTURED DYNAMIC SOLAR CORONA OBSERVED IN THE Hi-C TELESCOPE

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