SDO/AIA response to coronal hole, quiet Sun, active region, and flare plasma

O’Dwyer, B.; Zanna, G. Del; Mason, H. E.; Weber, Mark; Tripathi, Durgesh

doi:10.1051/0004-6361/201014872

Cited by 386 publications

(306 citation statements)

References 15 publications

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“…Later on in the decay phase (top middle panel of the figure), loops stand out in the 131 channel as much sharper structures with much of the wide envelop diminished. These loops are the same (cool) loops observed in the 171 band; they become visible in the 131 band because of the pronounced response at 0.4 MK (Fe VIII) in this bandpass (O'Dwyer et al 2010). It is not clear what produces the wide envelop in high-temperature EUV emission in the early phase.…”

Section: Timescales Of Euv Emissions In Flare Loopsmentioning

confidence: 59%

Long Duration Flare Emission: Impulsive Heating or Gradual Heating?

Qiu

Longcope

2016

ApJ

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Flare emissions in X-ray and EUV wavelengths have previously been modeled as the plasma response to impulsive heating from magnetic reconnection. Some flares exhibit gradually evolving X-ray and EUV light curves, which are believed to result from superposition of an extended sequence of impulsive heating events occurring in different adjacent loops or even unresolved threads within each loop. In this paper, we apply this approach to a long duration two-ribbon flare SOL2011-09-13T22 observed by the Atmosphere Imaging Assembly (AIA). We find that to reconcile with observed signatures of flare emission in multiple EUV wavelengths, each thread should be heated in two phases, an intense impulsive heating followed by a gradual, low-rate heating tail that is attenuated over 20-30 minutes. Each AIA resolved single loop may be composed of several such threads. The two-phase heating scenario is supported by modeling with both a zero-dimensional and a 1D hydrodynamic code. We discuss viable physical mechanisms for the two-phase heating in a post-reconnection thread.

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Section: Timescales Of Euv Emissions In Flare Loopsmentioning

confidence: 59%

Long Duration Flare Emission: Impulsive Heating or Gradual Heating?

Qiu

Longcope

2016

ApJ

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“…These SDO/AIA observations provide unprecedented coverage in terms of spatial and temporal resolutions, and can provide new diagnostic applications, once the atomic data are well understood. As shown in O'Dwyer et al (2010) andDel Zanna et al (2011), these bands are dominated by Fe x and Fe viii in normal quiet Sun conditions. However, several unidentified spectral lines have been observed in the AIA passbands with high-resolution grazing incidence solar spectrometers (cf.…”

Section: Introductionmentioning

confidence: 81%

Atomic data for astrophysics: Fe x soft X-ray lines

Zanna¹,

Storey

Badnell

et al. 2012

A&A

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New atomic calculations for Fe x are presented. They focus on the need to model the soft X-ray spectrum and in particular the line at 94.0 Å which is the dominant contribution to the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) 94 Å band in quiet Sun conditions. This line, and others in the band, are due to strong decays from n = 4 levels. We present new large-scale R-matrix (up to n = 4) and distorted-wave (DW, up to n = 6) scattering calculations for electron collisional excitation and compare them to earlier work. We find significant discrepancies with previous calculations. We show that resonances significantly increase the cross-sections for excitations from the ground state to some n = 4 levels, in particular to those in the 3s 2 3p 4 4s configuration. Cascading from higher levels is also important. We suggest a new identification for the 3s 3p 6 2 S 1/2 -3s 3p 5 4s 2 P 3/2 transition, that has a predicted intensity larger than the decays from the 3s 2 3p 4 4s levels which were identified by Edlén in 1936. The results presented here are relevant to our understanding of transitions from n = 4 levels in a wide range of other ions.

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“…The AIA data used here were taken in the 1600 Å, 304 Å, 171 Å, 193 Å, and 94 Å passbands at 12 s cadence and exposure time that varies during the flare. The response of these channels to different temperature plasma can be found in O'Dwyer et al (2010). The HMI measures Doppler shifts, intensity, and vector magnetic field using the Fe i 6173 Å absorption line.…”

Section: Aia/hmi/sdomentioning

confidence: 99%

Hαspectroscopy and multiwavelength imaging of a solar flare caused by filament eruption

Huang

Madjarska²,

Koleva

et al. 2014

A&A

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Context. We study a sequence of eruptive events including filament eruption, a GOES C4.3 flare, and a coronal mass ejection. Aims. We aim to identify the possible trigger(s) and precursor(s) of the filament destabilisation, investigate flare kernel characteristics, flare ribbons/kernels formation and evolution, study the interrelation of the filament-eruption/flare/coronal-mass-ejection phenomena as part of the integral active-region magnetic field configuration, and determine Hα line profile evolution during the eruptive phenomena. Methods. Multi-instrument observations are analysed including Hα line profiles, speckle images at Hα -0.8 Å and Hα + 0.8 Å from IBIS at DST/NSO, EUV images and magnetograms from the SDO, coronagraph images from STEREO, and the X-ray flux observations from Fermi and GOES. Results. We establish that the filament destabilisation and eruption are the main triggers for the flaring activity. A surge-like event with a circular ribbon in one of the filament footpoints is determined as the possible trigger of the filament destabilisation. Plasma draining in this footpoint is identified as the precursor for the filament eruption. A magnetic flux emergence prior to the filament destabilisation followed by a high rate of flux cancellation of 1.34 × 10 16 Mx s −1 is found during the flare activity. The flare X-ray lightcurves reveal three phases that are found to be associated with three different ribbons occurring consecutively. A kernel from each ribbon is selected and analysed. The kernel lightcurves and Hα line profiles reveal that the emission increase in the line centre is stronger than that in the line wings. A delay of around 5-6 min is found between the increase in the line centre and the occurrence of red asymmetry. Only red asymmetry is observed in the ribbons during the impulsive phases. Blue asymmetry is only associated with the dynamic filament.

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SDO/AIA response to coronal hole, quiet Sun, active region, and flare plasma

Cited by 386 publications

References 15 publications

Long Duration Flare Emission: Impulsive Heating or Gradual Heating?

Long Duration Flare Emission: Impulsive Heating or Gradual Heating?

Atomic data for astrophysics: Fe x soft X-ray lines

Hαspectroscopy and multiwavelength imaging of a solar flare caused by filament eruption

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