Response of Hinode XRT to quiet Sun, active region and flare plasma

O’Dwyer, B.; Zanna, G. Del; Mason, H. E.

doi:10.1051/0004-6361/201016346

Cited by 12 publications

(11 citation statements)

References 32 publications

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“…As we have found in previous cases, the results of automatic inversion methods are quite sensitive to the temperature range, and depend on the temperature bin size. For well-constrained cases, the results are very similar (Del Zanna et al 2011c;O'Dwyer et al 2014). histograms).…”

Section: Smm Fcssupporting

confidence: 67%

Elemental abundances and temperatures of quiescent solar active region cores from X-ray observations

Zanna¹,

Mason²

2014

A&A

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A brief review of studies of elemental abundances and emission measures in quiescent solar active region cores is presented. Hinode EUV Imaging Spectrometer (EIS) observations of strong iron spectral lines have shown sharply peaked distributions around 3 MK. EIS observations of lines emitted by a range of elements have allowed good estimates of abundances relative to iron. However, X-ray observations are required to measure the plasma emission above 3 MK and the abundances of oxygen and neon. We revisit, using upto-date atomic data, older X-ray observations obtained by a sounding rocket and by the Solar Maximum Mission (SMM) Flat Crystal Spectrometer (FCS). We find that the Fe/O and Fe/Ne ratios are normally increased by a factor of 3.2, compared to the photospheric values. Similar results are obtained from FCS observations of six quiescent active region cores. The FCS observations also indicate that the emission measure above 3 MK has a very steep negative slope, with very little plasma observed at 5 MK or above.

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Section: Smm Fcssupporting

confidence: 67%

Elemental abundances and temperatures of quiescent solar active region cores from X-ray observations

Zanna¹,

Mason²

2014

A&A

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“…Observations in multiple XRT bands can also provide temperature measurements in flares (Narukage et al 2011(Narukage et al , 2014O'Dwyer et al 2014). We compare the temperature diagnostic obtained with AIA with that derived by using the ratio of the XRT Be_thick and Al_thick images (Figure 17).…”

Section: Temperature Diagnostics With Sdo/aia and Hinode/xrtmentioning

confidence: 99%

Simultaneous Iris and Hinode/Eis Observations and Modeling of the 2014 October 27 X2.0 CLASS Flare

Polito

Reep

Reeves

et al. 2016

ApJ

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105

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We present a study of the X2-class flare which occurred on 2014 October 27 and was observed with the Interface Region Imaging Spectrograph (IRIS) and the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. Thanks to the high cadence and spatial resolution of the IRIS and EIS instruments, we are able to compare simultaneous observations of the Fe XXI1354.08 Åand Fe XXIII263.77 Åhigh-temperature emission (10 MK) in the flare ribbon during the chromospheric evaporation phase. We find that IRIS observes completely blueshifted Fe XXIline profiles, up to 200 km s −1 during the rise phase of the flare, indicating that the site of the plasma upflows is resolved by IRIS. In contrast, the Fe XXIIIline is often asymmetric, which we interpret as being due to the lower spatial resolution of EIS. Temperature estimates from SDO/AIA and Hinode/XRT show that hot emission (log(T[K]) >7.2) is first concentrated at the footpoints before filling the loops. Density-sensitive lines from IRIS and EIS give estimates of electron number density of 10 12 cm −3 in the transition region lines and 10 10 cm −3 in the coronal lines during the impulsive phase. In order to compare the observational results against theoretical predictions, we have run a simulation of a flare loop undergoing heating using the HYDRAD 1D hydro code. We find that the simulated plasma parameters are close to the observed values that are obtained with IRIS, Hinode, and AIA. These results support an electron beam heating model rather than a purely thermal conduction model as the driving mechanism for this flare.

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“…These observations are typically taken at a relatively low cadence, with spectra taken at one position every few minutes. Observations from XRT and AIA in the 131 and 94 Å channels, which observe Fe XXI 128.75 Å and Fe XVIII 93.93 Å, provide information on the hightemperature emission on much shorter timescales (for a discussion of the XRT and AIA temperature responses see O'Dwyer et al 2010O'Dwyer et al , 2014.…”

Section: Observationsmentioning

confidence: 99%

Transition Region and Chromospheric Signatures of Impulsive Heating Events. I. Observations

Warren

Reep

Crump

et al. 2016

ApJ

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We exploit the high spatial resolution and high cadence of the Interface Region Imaging Spectrograph (IRIS) to investigate the response of the transition region and chromosphere to energy deposition during a small flare. Simultaneous observations from the Reuven Ramaty High Energy Solar Spectroscopic Imager provide constraints on the energetic electrons precipitating into the flare footpoints, while observations of the X-Ray Telescope, Atmospheric Imaging Assembly, and Extreme Ultraviolet Imaging Spectrometer (EIS) allow us to measure the temperatures and emission measures from the resulting flare loops. We find clear evidence for heating over an extended period on the spatial scale of a single IRIS pixel. During the impulsive phase of this event, the intensities in each pixel for the Si IV 1402.770 Å, C II 1334.535 Å, Mg II 2796.354 Å, and O I 1355.598 Å emission lines are characterized by numerous small-scale bursts typically lasting 60 s or less. Redshifts are observed in Si IV, C II, and Mg II during the impulsive phase. Mg II shows redshifts during the bursts and stationary emission at other times. The Si IV and C II profiles, in contrast, are observed to be redshifted at all times during the impulsive phase. These persistent redshifts are a challenge for one-dimensional hydrodynamic models, which predict only short-duration downflows in response to impulsive heating. We conjecture that energy is being released on many small-scale filaments with a power-law distribution of heating rates.

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Response of Hinode XRT to quiet Sun, active region and flare plasma

Cited by 12 publications

References 32 publications

Elemental abundances and temperatures of quiescent solar active region cores from X-ray observations

Elemental abundances and temperatures of quiescent solar active region cores from X-ray observations

Simultaneous Iris and Hinode/Eis Observations and Modeling of the 2014 October 27 X2.0 CLASS Flare

Transition Region and Chromospheric Signatures of Impulsive Heating Events. I. Observations

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