J/ApJ/891/54 Solar X-ray flares and associated CME speeds & widths (Ling+, 2020)
Peak temperatures of large solar X-ray flares and associated CME speeds and
widths.
Ling A.G., Kahler S.W.
<Astrophys. J., 891, 54 (2020)>
=2020ApJ...891...54L 2020ApJ...891...54L
ADC_Keywords: Sun; Stars, flare; X-ray sources
Keywords: Solar flares ; Solar coronal mass ejections ;
Solar coronal mass ejection shocks ; Solar x-ray flares ;
Solar flare spectra ; Solar active regions
Abstract:
We recently repeated an earlier analysis by Garcia showing that large
(≥M3.0) solar X-ray flares associated with solar energetic particle
(SEP) events have significantly lower peak X-ray flux ratios
R=(0.04-0.5nm)/(0.1-0.8nm), proxies for flare peak temperatures, than
those without SEP events. As we expect SEP events to be produced by
shocks ahead of fast coronal mass ejections (CMEs), a smaller R for an
X-ray flare of a given peak flux Fp should also be more likely to be
accompanied by a fast (Vcme>1000km/s) CME. We confirm this
expectation, examine the role played by the ratios R in correlations
between Fp and CME speeds Vcme, and then compare CME widths W, Vcme,
and R with each other. We consider an apparent conflict between a
global scaling model of eruptive events showing Vcme scaling with
higher R and our confirmation that the Garcia analysis implies that
faster CMEs are associated with flares of lower R. The R values are
examined for 16 large flares of the well-studied AR 12192, for which
nearly all flares had no associated CMEs. Those flares share the same
high values of R as other active region (AR) flares with no CMEs. We
also find that small (<M3.0) flares of filament eruptions leading to
SEP events share the lower R values of larger flares with fast CMEs.
Description:
We begin with the same KL18 (Kahler & Ling 2018JSWSC...8A..47K 2018JSWSC...8A..47K) list
of all GOES/XRS ≥M3.0 flares with given flare locations from 1998 to
2016 taken from ftp.ngdc.noaa.gov. There were 433 flares without and
75 flares with ≥10 pfu SEP events in that list. We changed the flare
locations of four events and added five events from 2014 October,
originally excluded due to lack of flare locations, to make a total of
513 flare events. We then added 16 additional flares in 2017 from
ftp.swpc.noaa.gov, bringing the new total to 529. As in KL18, we
consider separately the eastern and western hemisphere flares.
The timing and location of each X-ray flare was compared with coronal
mass ejections (CMEs) reported on the Solar and Heliospheric
Observatory (SOHO) - Large Angle and Spectromeric Coronagraph Experiment
(LASCO) website (http://cdaw.gsfc.nasa.gov/CME_list/index.html) to
determine the CME association, if any, for each flare.
LASCO data gaps during 51 flares reduced the comparisons to a total of
478 cases, which were then compared with the CME-flare associations at
http://cdaw.gsfc.nasa.gov/pub/yashiro/flare_cme/fclist_pub.txt
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 62 451 X-ray flares >M3 and associated coronal mass ejections
(CMEs) and solar energetic particle (SEP) events
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See also:
J/A+A/304/563 : Cool X-ray flares of Sun with GOES (Phillips+, 1995)
J/ApJ/831/105 : Global energetics of solar flares. IV. CME (Aschwanden, 2016)
J/ApJ/833/284 : Quasi-periodic pulsations in solar flares (Inglis+, 2016)
J/ApJ/871/16 : Sun active regions from 1976-2017 (Jiang+, 2019)
J/ApJ/881/1 : Global energetics of solar flares. VIII. (Aschwanden+, 2019)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 yr Event.Y [1998/2017] Year of the flare
6- 7 I2 "month" Event.M Month of the flare
9- 10 I2 d Event.D Day of the flare
12- 13 I2 h Peak.h Hour of X-ray flare peak
15- 16 I2 min Peak.m Minute of X-ray flare peak
18- 22 A5 --- Class Flare Class
24- 29 A6 --- Loc Solar Location of flare
31- 38 E8.2 --- R [0.15/0.69] Peak X-ray Ratio
40- 43 I4 km/s Vcme [113/3387]? CME Speed
45- 47 I3 deg Width [11/360]? CME Width
49- 50 I2 d Day [1/31]? SEP Onset day
52- 55 I4 h Hour ? SEP Onset UT hour
57- 62 F6.1 --- Ip [1.4/8000]? SEP Peak intensity (1)
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Note (1): In units of pfu (proton flux unit = 1 proton/(cm2.s.sr).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 05-Aug-2021