J/ApJS/253/29 Solar flare variability from GOES-15 Lyα obs. (Lu+, 2021)
Catalog and statistical examinations of Lyα solar flares from
GOES/EUVS-E measurements.
Lu L., Feng Li, Li D., Ying B., Li H., Gan W., Li Y., Zhou J.
<Astrophys. J. Suppl. Ser., 253, 29 (2021)>
=2021ApJS..253...29L 2021ApJS..253...29L
ADC_Keywords: Sun; Stars, flare; Ultraviolet
Keywords: Astrostatistics distributions ; Solar flares ;
Solar ultraviolet emission ; Algorithms
Abstract:
The Lyman-alpha (Lyα) line of neutral hydrogen at 121.6nm is by
far the brightest emission line in the vacuum ultraviolet spectral
range of the Sun. The emission at this line could be a major energy
input to the upper layers of the Earth's atmosphere, strongly
impacting the geospace environment. The Geostationary Operational
Environmental Satellite (GOES) series, starting with GOES-13, began to
carry a multichannel Extreme UltraViolet Sensor (EUVS) with one
channel (E-channel) targeting the Lyα line. In the present work,
we produce a Lyα flare catalog from the GOES-15/EUVS-E data
between 2010 April 8 and 2016 June 6 with an automatic flare detection
algorithm. This algorithm is designed to search events at various
scales and find their real start and end times. Based on the obtained
flare list, statistics on the temporal behavior such as the duration,
rise, and decay times, and the event asymmetries of Lyα flares
is presented. On average (defined by the median of the distributions),
the duration, rise and decay times of the flares were estimated to be
20.8 minutes, 5.6 minutes, and 14.2 minutes, respectively. We also
discuss the frequency distributions of the peak flux and the fluence
of Lyα flares, both of which reveal power-law behaviors with
power-law indices of 2.71±0.06 and 2.42±0.06, respectively,
implying that more flares are accumulated at small scales and these
small-scale events play an important role in explaining the violent
solar energy release.
Description:
The Geostationary Operational Environmental Satellite (GOES) series of
spacecraft, starting with GOES-1, have been observing the Sun nearly
uninterruptedly in two broadband SXR channels (0.5-4Å and 1-8Å)
via their X-ray Sensor instruments since their first launch in 1975.
In addition to the X-ray sensor, since the launch of GOES-13 in 2006,
the GOES series of spacecraft have started to carry a multichannel
Extreme Ultraviolet Sensor (EUVS), dedicated to measuring the full-Sun
extreme ultraviolet (EUV) emission in five channels (A, B, C, D, and
E) between 50 and 1270Å. The E-channel (1180-1270Å) is dominated
by the Lyα line at 1216Å.
In this paper, we analyzed the Lyα observations from 2010 April 8
to 2016 June 6 by GOES-15/EUVS-E.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 80 2038 Catalogue of events
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See also:
J/A+A/304/563 : Cool X-ray flares of Sun with GOES (Phillips+, 1995)
J/ApJ/757/94 : Solar flares observed with GOES and AIA (Aschwanden, 2012)
J/ApJ/759/69 : 1995-2005 solar electron events with WIND/3DP (Wang+, 2012)
J/A+A/574/A37 : Movies of 2012-10-16 solar flare (Dalmasse+, 2015)
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 : Studies of solar white-light flares (Namekata+, 2017)
J/ApJ/871/16 : Sun active regions from 1976-2017 (Jiang+, 2019)
J/ApJ/885/49 : Global energetics of solar flares. IX. (Aschwanden, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/2038] Flare index
6- 9 I4 yr Obs.Y [2010/2016] Observation year
11- 12 I2 "month" Obs.M Observation month
14- 15 I2 d Obs.D Observation day
17- 18 I2 h Start.h Flare start time hour
20- 21 I2 min Start.m Flare start time minute
23- 24 I2 s Start.s Flare start time second
26- 27 I2 h Peak.h Flare peak time hour
29- 30 I2 min Peak.m Flare peak time minute
32- 33 I2 s Peak.s Flare peak time second
35- 36 I2 h End.h Flare end time hour
38- 39 I2 min End.m Flare end time minute
41- 42 I2 s End.s Flare end time second
44- 48 F5.1 min Dur [2.2/195.3] Duration of event
50- 56 F7.4 10-3W/m2 Fstart [6.04/10.25] Initial flux
58- 64 F7.4 10-3W/m2 Fpk [6.11/11] Peak flux
66- 72 F7.4 10-3W/m2 Fend [6.05/10.5] End flux
74- 80 F7.4 % Signif [0.8/26.5] Peak flux increase (1)
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Note (1): Peak irradiance contrast relative to the greater value of start/end
fluxes, in %.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 05-May-2021