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J/ApJ/832/27     Global energetics of solar flares. III.     (Aschwanden+, 2016)

Global energetics of solar flares. III. Nonthermal energies. Aschwanden M.J., Holman G., O'Flannagain A., Caspi A., McTiernan J.M., Kontar E.P. <Astrophys. J., 832, 27-27 (2016)> =2016ApJ...832...27A (SIMBAD/NED BibCode)
ADC_Keywords: Sun ; Stars, flare ; Models Keywords: radiation mechanisms: nonthermal; Sun: flares; Sun: particle emission; Sun: X-rays, gamma rays Abstract: This study entails the third part of a global flare energetics project, in which Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) data of 191 M and X-class flare events from the first 3.5yrs of the Solar Dynamics Observatory mission are analyzed. We fit a thermal and a nonthermal component to RHESSI spectra, yielding the temperature of the differential emission measure (DEM) tail, the nonthermal power-law slope and flux, and the thermal/nonthermal cross-over energy eco. From these parameters, we calculate the total nonthermal energy Ent in electrons with two different methods: (1) using the observed cross-over energy eco as low-energy cutoff, and (2) using the low-energy cutoff ewt predicted by the warm thick-target bremsstrahlung model of Kontar et al. Based on a mean temperature of Te=8.6MK in active regions, we find low-energy cutoff energies of ewt=6.2±1.6keV for the warm-target model, which is significantly lower than the cross-over energies eco=21±6keV. Comparing with the statistics of magnetically dissipated energies Emag and thermal energies Eth from the two previous studies, we find the following mean (logarithmic) energy ratios with the warm-target model: Ent=0.41Emag, Eth=0.08Emag, and Eth=0.15Ent. The total dissipated magnetic energy exceeds the thermal energy in 95% and the nonthermal energy in 71% of the flare events, which confirms that magnetic reconnection processes are sufficient to explain flare energies. The nonthermal energy exceeds the thermal energy in 85% of the events, which largely confirms the warm thick-target model. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 88 190 Nonthermal energy parameters derived in 191 flare events observed with RHESSI
See also: J/ApJ/831/105 : Global energetics of solar flares. IV. CME (Aschwanden, 2016) J/ApJ/802/53 : Global energetics of solar flares. II. (Aschwanden+, 2015) J/A+A/574/A37 : Movies of 2012-10-16 solar flare (Dalmasse+, 2015) J/ApJ/797/50 : Global energetics of solar flares. I. (Aschwanden+, 2014) J/ApJ/774/L27 : Solar flares predictors (Yang+, 2013) J/ApJ/759/69 : Solar electron events (1995-2005) with WIND/3DP (Wang+, 2012) J/ApJ/757/94 : Solar flares observed with GOES and AIA (Aschwanden, 2012) J/ApJ/747/L41 : Solar flares probabilities (Bloomfield+, 2012) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Index number 5- 14 A10 "Y/M/D" Obs.date Date of Flare start 16- 20 A5 "h:m" Obs.time Time of Flare start 22- 25 A4 --- Cl GOES class 27- 32 A6 --- Pos Heliographic position 34- 38 I5 s Dur [160/20740] Soft X-ray flare duration 40- 44 I5 ct/s PkCts [30/53158] Peak counts 46- 52 E7.1 ct/s Cts Total counts 54- 55 I2 keV LowE [6/16] Lower bounds of fitted energy range 57- 58 I2 keV UpE [20/50] Upper bounds of fitted energy range 60- 63 F4.1 keV Cutoff [1.6/11.7] Warm-target lower cutoff energy (1) 65- 71 E7.1 10-7J Ewt Nonthermal energy, Ewt; in ergs 73- 79 F7.4 --- ERatio1 [0.002/76]?=0 Ratio of thermal to warm-target nonthermal energies, Eth/Ewt 81 A1 --- f_ERatio1 [*] Flag on ERatio1 (2) 83- 88 F6.3 --- ERatio2 [0.002/39]?=0 Ratio of warm-target nonthermal to magnetic energies, Ewt/Emag
Note (1): For a mean temperature of Te = 8.6 MK in flaring active regions. Note (2): * = Questionable solar flare event, detected in the front detectors without position.
History: From electronic version of the journal References: Aschwanden et al. Paper I. 2014ApJ...797...50A Cat. J/ApJ/797/50 Aschwanden et al. Paper II. 2015ApJ...802...53A Cat. J/ApJ/802/53 Aschwanden et al. Paper III. 2016ApJ...832...27A This catalog Aschwanden M.J. Paper IV. 2016ApJ...831..105A Cat. J/ApJ/831/105
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Feb-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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