J/ApJ/881/1 Global energetics of solar flares. VIII. (Aschwanden+, 2019)
Global energetics of solar flares.
VIII. The low-energy cutoff.
Aschwanden+, Aschwanden M.J., Kontar E.P., Jeffrey N.L.S.
<Astrophys. J., 881, 1 (2019)>
=2019ApJ...881....1A 2019ApJ...881....1A
ADC_Keywords: Solar system; Sun; Spectroscopy; X-ray sources; Stars, flare
Keywords: magnetic reconnection ; Sun: corona ; Sun: flares
Abstract:
One of the key problems in solar flare physics is the determination of
the low-energy cut-off: the value that determines the energy of
nonthermal electrons and hence flare energetics. We discuss different
approaches to determine the low-energy cut-off in the spectrum of
accelerated electrons: (I) the total electron number model, (II) the
time-of-flight model (based on the equivalence of the time-of-flight
and the collisional deflection time), (III) the warm target model of
Kontar et al., and (IV) the model of the spectral cross-over between
thermal and nonthermal components. We find that the first three models
are consistent with a low-energy cutoff with a mean value of ∼10keV,
while the cross-over model provides an upper limit for the low-energy
cutoff with a mean value of ∼21keV. Combining the first three models
we find that the ratio of the nonthermal energy to the dissipated
magnetic energy in solar flares has a mean value of qE=0.57±0.08,
which is consistent with an earlier study based on the simplified
approximation of the warm target model alone (qE=0.51±0.17). This
study corroborates the self-consistency between three different
low-energy cutoff models in the calculation of nonthermal flare
energies.
Description:
We use the same Ramaty High Energy Solar Spectroscopic Imager (RHESSI)
data of 191 flare events as previously analyzed in Paper III, using
the Object Spectral Executive (OSPEX) software.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 150 190 Observables and model energies for flare hard X-ray
emission in 143 M and X-class flare events
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See also:
J/ApJ/757/94 : Solar flares observed with GOES and AIA (Aschwanden, 2012)
J/ApJ/797/50 : Global energetics of solar flares. I. (Aschwanden+, 2014)
J/ApJ/802/53 : Global energetics of solar flares. II. (Aschwanden+, 2015)
J/ApJ/831/105 : Global energetics of solar flares. IV. CME (Aschwanden, 2016)
J/ApJ/832/27 : Global energetics of solar flares. III. (Aschwanden+, 2016)
J/ApJ/833/284 : Quasi-periodic pulsations in solar flares (Inglis+, 2016)
J/ApJ/845/36 : Complex network for solar active regions (Daei+, 2017)
J/ApJ/847/115 : The solar flare complex network (Gheibi+, 2017)
J/ApJ/851/91 : Statistical studies solar white-light flares (Namekata+, 2017)
http://hesperia.gsfc.nasa.gov/ : OSPEW software homepage
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/395] Sequential flare event identifier
5- 8 I4 yr Obs.Y [2010/2014] Observation year UT
9- 10 I2 "month" Obs.M Observation month UT
11- 12 I2 d Obs.D Observation day UT
14- 15 I2 h Obs.H Observation hour UT
16- 17 I2 min Obs.min Observation minute UT
19- 22 A4 --- Cl Geostationary Operational Environmental
Satellite (GOES) M or X-class
24- 29 A6 --- Pos Heliographic position
31- 35 I5 s Dur [160/20740] Hard X-ray flare duration
37- 45 F9.5 cm-3 EM49 [0/240.7] Emission measure
47- 51 F5.2 MK Tmax [3.12/38.35] Temperature max
53- 57 F5.2 --- e1 [50.0] Refererce energy σ1, fixed to 50
59- 67 F9.7 cm2.s/keV I1 [5.8e-06/0.23] Photon Flux
69- 73 F5.2 --- gamma [2.76/10.39] Spectral slope, γ
75- 79 F5.2 Mm L [1.72/36.32] Length Scale
81- 86 F6.2 cm-3 n10 [0/136.12] Density maximum
88- 94 F7.2 cm-3 nb10 [0/2582.54] Density preflare
96-100 F5.1 keV Eco-en [0.1/194.3] Cutoff energy, el model
102-105 F4.1 keV Eco-wt [1.6/30.5] Cutoff energy, wt model
107-111 F5.1 keV Eco-tof [0/107.7] Cutoff energy, tof model
113-116 F4.1 keV Eco-co [10/30] Cutoff energy, co model
118-125 F8.4 10+24J Ent-el [0/505.2834] Nonthermal energy, el model
127-134 F8.4 10+24J Ent-wt [0.0009/999] Nonthermal energy, wt model
136-143 F8.4 10+24J Ent-tof [0/999] Nonthermal energy, tof model
145-150 F6.4 10+24J Ent-co [0/3.6127] Nonthermal energy, co model
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History:
From electronic version of the journal
References:
Aschwanden et al. Paper I: 2014ApJ...797...50A 2014ApJ...797...50A cat: J/ApJ/797/50
Aschwanden et al. Paper II: 2015ApJ...802...53A 2015ApJ...802...53A cat: J/ApJ/802/53
Aschwanden et al. Paper III: 2016ApJ...832...27A 2016ApJ...832...27A cat: J/ApJ/832/27
Aschwanden et al. Paper IV: 2016ApJ...831..105A 2016ApJ...831..105A cat: J/ApJ/831/105
Aschwanden et al. Paper V: 2017ApJ...836...17A 2017ApJ...836...17A
Aschwanden et al. Paper VI: 2017ApJ...847...27A 2017ApJ...847...27A
Aschwanden et al. Paper VII: 2019ApJ...877..149A 2019ApJ...877..149A
Aschwanden et al. Paper IX: 2019ApJ...885...49A 2019ApJ...885...49A
Aschwanden et al. Paper X: 2020ApJ...895..134A 2020ApJ...895..134A
Aschwanden et al. Paper XI: 2020ApJ...897...16A 2020ApJ...897...16A
Aschwanden et al. Paper XII: 2020ApJ...903...23A 2020ApJ...903...23A
(End) Prepared by [AAS], Coralie Fix [CDS], 18-Dec-2020