J/ApJ/797/50 Global energetics of solar flares. I. (Aschwanden+, 2014)
Global energetics of solar flares. I. Magnetic energies.
Aschwanden M.J., Xu Y., Jing J.
<Astrophys. J., 797, 50 (2014)>
=2014ApJ...797...50A 2014ApJ...797...50A
ADC_Keywords: Sun ; Magnetic fields ; Ultraviolet
Keywords: magnetic fields; Sun: flares; Sun: UV radiation
Abstract:
We present the first part of a project on the global energetics of
solar flares and coronal mass ejections that includes about 400 M- and
X-class flares observed with Atmospheric Imaging Assembly (AIA) and
Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics
Observatory (SDO). We calculate the potential (Ep), the nonpotential
(Enp) or free energies (Efree=Enp-Ep), and the
flare-dissipated magnetic energies (Ediss). We calculate these
magnetic parameters using two different NLFFF codes: the COR-NLFFF
code uses the line-of-sight magnetic field component Bz from HMI to
define the potential field, and the two-dimensional (2D) coordinates
of automatically detected coronal loops in six coronal wavelengths
from AIA to measure the helical twist of coronal loops caused by
vertical currents, while the PHOT-NLFFF code extrapolates the
photospheric three-dimensional (3D) vector fields. We find agreement
between the two codes in the measurement of free energies and
dissipated energies within a factor of ≲3. The size distributions of
magnetic parameters exhibit powerlaw slopes that are approximately
consistent with the fractal-diffusive self-organized criticality
model. The magnetic parameters exhibit scaling laws for the
nonpotential energy, Enp∝Ep1.02, for the free energy,
Efree∝Ep1.7 and Efree∝Bφ1.0L1.5, for
the dissipated energy, Ediss∝Ep1.6 and
Ediss∝Efree0.9 , and the energy dissipation volume,
V∝Ediss1.2. The potential energies vary in the range of
Ep=1x1031-4x1033erg, while the free energy has a ratio of
Efree/Ep~1%-25%. The Poynting flux amounts to
Fflare~5x108-1010erg/cm2/s during flares, which averages
to FAR~6x106erg/cm2/s during the entire observation period
and is comparable with the coronal heating rate requirement in active
regions.
Description:
The data set we are analyzing for this project on the global
energetics of flares includes all M- and X-class flares observed with
the Solar Dynamics Observatory (SDO) during the first 3.5yr of the
mission (2010 June 1 to 2014 January 31), which amounts to 399 flare
events. Magnetic energies are determined for events that have a
heliographic longitude of ≲45° (177 events), of which 5 events
contained incomplete or corrupted Atmospheric Imaging Assembly (AIA)
data, so that we are left with 172 events suitable for magnetic data
analysis.
The analyzed SDO data set includes EUV images observed with the AIA,
as well as magnetograms from the Helioseismic and Magnetic Imager
(HMI). The SDO started observations on 2010 March 29 and has produced
essentially continuous data of the full Sun since then.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 89 173 Magnetic energy parameters calculated with the
COR-NLFFF code for 172 M and X-class flares wuth
a longitude difference of <45 degrees to the
central meridian
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See also:
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/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)
J/A+A/304/563 : Cool X-ray flares of Sun with GOES (Phillips+, 1995)
http://aia.lmsal.com/ : Atmospheric Imaging Assembly home page
http://www.lmsal.com/~aschwand/RHESSI/flare_energetics.html : Global Flare
Energetics Survey home page project
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [3/399] Solar flare number
5- 14 A10 "YYYY/MM/DD" Fl.date Date of flare start
16- 20 A5 "h:m" Fl.time Time of flare start
22- 25 A4 --- Cl GOES class (M1-X5.4)
27- 32 A6 --- Pos Heliographic position
34- 36 F3.1 deg Angle [1/8] Magnetic field misalignment angle µ
38- 41 I4 10+23J Ep [85/3949] Potential energy; 10+30erg
43- 45 I3 10+23J e_Ep [3/788] Uncertainty in Ep
47- 49 I3 10+23J Efree [1/951] Free energy; 10+30erg
51- 53 I3 10+23J e_Efree [0/324] Uncertainty in Efree
55- 59 F5.3 --- Ratio [0/0.9] Energy ratio; Efree/Ep
61- 64 I4 10+23J Ediss [0/1546] Dissipated energy; 10+30erg
66- 68 I3 10+23J e_Ediss [0/224] Uncertainty in Ediss
70- 73 I4 1.39x10+20W Pdiss [0/1021] Peak dissipation rate;
in 10+30erg/0.2hr unit
75- 77 I3 --- e_Pdiss [0/222] Uncertainty in Pdis
79- 81 I3 Mm L [0/236] Length scale (in 1000km)
83- 84 I2 Mm e_L [0/16] Uncertainty in L
86- 89 F4.2 h T [0.08/4.1] Duration
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History:
From electronic version of the journal
References:
Aschwanden et al. Paper I. 2014ApJ...797...50A 2014ApJ...797...50A This catalog
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 M.J. Paper IV. 2016ApJ...831..105A 2016ApJ...831..105A Cat. J/ApJ/831/105
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 22-Jul-2015