The decay of the 1973 August 9 flare

Dere, K. P.; Cook, J. W.

doi:10.1086/157013

Cited by 86 publications

(50 citation statements)

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“…) was obtained from AR intensities measured by the EUV Imaging Spectrometer (EIS; Culhane et al 2007) on Hinode. The flare DEM was based on observations of an M2 X-ray class flare by Dere & Cook (1979).…”

Section: Discussionmentioning

confidence: 99%

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

O’Dwyer¹,

Zanna²,

Mason³

et al. 2010

A&A

386

292

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Aims. We examine the contribution of spectral lines and continuum emission to the EUV channels of the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) in different regions of the solar atmosphere. Methods. Synthetic spectra were obtained using the CHIANTI atomic database and sample differential emission measures for coronal hole, quiet Sun, active region and flare plasma. These synthetic spectra were convolved with the effective area of each channel, in order to determine the dominant contribution in different regions of the solar atmosphere. Results. We highlight the contribution of particular spectral lines which under certain conditions can affect the interpretation of SDO/AIA data.

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Section: Discussionmentioning

confidence: 99%

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

O’Dwyer¹,

Zanna²,

Mason³

et al. 2010

A&A

386

292

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show abstract

“…Evidence for multithermal plasmas has been found by EUV and SXR spectroscopy (e.g., Dere & Cook 1979;McTiernan et al 1999;Chifor et al 2007) and by RHESSI HXR observations (Aschwanden 2007;Caspi & Lin 2010;Jain et al 2011). Recent studies using multiband EUV images from SDO/AIA Ryan et al 2014;Aschwanden et al 2015) and EUV spectra by SDO/EVE (Warren et al 2013;Kennedy et al 2013;Caspi et al 2014b) and by Hinode/EIS (Graham et al 2013) have finally provided well-constrained DEM distributions and have shown conclusively that the thermal component in solar flares is indeed multithermal in nature.…”

Section: Evolutionary Effects and Multithermalitymentioning

confidence: 94%

Constraints on energy release in solar flares from RHESSI and GOES X-ray observations

Warmuth

Mann

2016

A&A

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Aims. We constrain energy release and particle acceleration processes in solar flares by means of comprehensively characterizing the physical parameters of both the thermal plasma and the accelerated nonthermal particles using X-ray data. Our aim is to bridge the gap between detailed case studies and large statistical studies. Methods. We obtained time series of spectral fits and images for 24 flares ranging from GOES class C3.4 to X17.2 using RHESSI hard X-ray observations. These data were used to derive basic physical parameters for the thermal plasma (using the isothermal approximation) and the injected nonthermal electrons (assuming the thick-target model). For the thermal component, this was supplemented by GOES soft X-ray data. We derived the ranges and distributions of the various parameters, the scaling with flare importance, and the relation between thermal parameters derived from RHESSI and GOES. Finally, we investigated the relation between thermal and nonthermal parameters. Results. Temperature and emission measure of the thermal plasma are strongly correlated with the peak GOES X-ray flux. Higher emission measures result both from a larger source volume and a higher density, with the latter effect being more important. RHESSI consistently gives higher temperatures and lower emission measures than GOES does, which is a signature of a multithermal plasma. The discrepancy between RHESSI and GOES is particularly pronounced in the early flare phase, when the thermal X-ray sources tend to be large and located higher in the corona. The energy input rate by nonthermal electrons is correlated with temperature and with the increase rate of emission measure and thermal energy. Conclusions. The derived relations between RHESSI-and GOES-derived thermal parameters and the relation between thermal parameters and energy input by nonthermal electrons are consistent with a two-component model of the thermal flare plasma. Both RHESSI and GOES observe a cooler plasma component (≈10−25 MK) that is generated by chromospheric evaporation caused by a nonthermal electron beam. In addition, a hotter component (≥25 MK) is only detected by RHESSI; this component is more consistent with direct in situ heating of coronal plasma. With the exception of the early impulsive phase, RHESSI observes a combination of the evaporated and the directly heated component.

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“…The third column shows the ion giving rise to the spectral line and the fourth column provides the transition. The fourth column gives the intensity expected from a solar flare using a differential emission measure distribution derived by Dere & Cook (1979). The intensities are calculated from the differential emission measure, which spans the temperature range 3 10 4 to 2.5 10 7 K, with the elemental abundances of Allen (1973) and the ionization equilibria of Arnaud & Rothenflug (1985).…”

Section: Observed and Predicted Spectra: 50 To 1100åmentioning

confidence: 99%

CHIANTI - an atomic database for emission lines

Dere

Landi

Mason

et al. 1997

Astron. Astrophys. Suppl. Ser.

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1,947

1,669

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Abstract. A comprehensive set of accurate atomic data is required for analyses of astrophysical and solar spectra. CHIANTI provides a database of atomic energy levels, wavelengths, radiative data and electron excitation data for ions which are abundant in cosmic plasmas. The most recent electron excitation data have been assessed and stored following the method of Burgess & Tully (1992). The current version is essentially complete for specifying the emission spectrum at wavelengths greater than 50Å. A list of observed lines in the spectral region between 50 and 1100Å has been compiled and compared with the lines predicted by the CHIANTI database. The CHIANTI database reproduces the vast majority of lines observed at these wavelengths. CHIANTI includes IDL (Interactive Data Language) routines to calculate optically thin synthetic spectra for equilibrium conditions. IDL routines to calculate theoretical line intensities required for electron density or temperature diagnostics and emission measure studies are also included. The CHIANTI atomic database and supporting IDL routines are available by anonymous FTP.

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The decay of the 1973 August 9 flare

Cited by 86 publications

References 0 publications

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

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

Constraints on energy release in solar flares from RHESSI and GOES X-ray observations

CHIANTI - an atomic database for emission lines

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