1. Solar Energetic Electrons and Radio Emission Signatures
Susan W. Samwel
National Research Institute of Astronomy and Geophysics (NRIAG), 11421, Helwan, Cairo, Egypt
Rositsa Miteva
Space Research and Technology Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

2. SEPs are generated by solar activity (flares, CMEs) (ongoing debate)??
Introduction
Solar energetic particle (SEP) is a generic term used to describe an elevated flux of electrons, protons and heavy ions that are energized during eruptive event at the Sun to keV -GeV and observed in situ
CME
flare
SEPs are generated by solar activity (flares, CMEs) (ongoing debate)??
source
surface
SEPs
in situ solar energetic particles,
particles/(cm2 sr s MeV)
Energetic particles escape from the corona, sustain various transport effects in the IP space before being finally detected.

3. Introduction Solar Energetic Particle Catalogs …Why??
Solar energetic particles (SEPs) are an important aspect of space weather research due to the potential radiation risk they carry.
planning and carrying out of human flights to space require an improved knowledge and successful forecasting of the energetic protons and electrons released from the Sun.
Solar Energetic Particle Catalogs …Why??
Solar Energetic Proton Catalogs
Miteva, R., Samwel, S.W. & Costa-Duarte, M.V. Sol Phys (2018) 293: 27.
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

4. Novel Solar Energetic Electron Catalog??
Solar Energetic Electron Catalogs
Lists
No. of events/Energy
instrument
Duration
Krucker et al. (1999)
12 events (< 1keV)
58 events (>25 keV)
Wind /3-DP
Haggerty and Roelof (2002)
79 events ( keV)
ACE/EPAM
Aug Sep. 2000
Krucker et al. (2007)
16 events (>50keV)
Vainio et al., 2013
SEPServer Cat.
315 events
SOHO/EPHIN
Novel Solar Energetic Electron Catalog??
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5. Onset time: 3σ above background level
ACE/EPAM Electron Events Catalog
Data Analysis
Instrument: Electron Proton and Alpha monitor (EPAM) aboard the ACE spacecraft
Time coverage: 1997– Resolution: 12 sec
Energy range: –175 keV (low) –315 keV (high)
Onset time: 3σ above background level
Peak intensity, Je:
electrons/cm2 sr s keV
~1240 electron events
~990 electron events
CDAW database for ACE/EPAM data:
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

6. ACE/EPAM Electron Event Catalog
keV)-1
-GOES Soft X-ray flare listing,
- Solar monitor.org
- SGD reports
SOHO/LASCO catalog
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

7. Distribution of electron events over SC23
Electron events (SC23) 103–175 keV: 840 events
175–315 keV: 680 events
Electron events (SC24) 103–175 keV: 407 events
175–315 keV: 319 events
Solar origin identification (SC23)
Flares: 66% CMEs: 55%
Solar origin identification (SC24)
Flares: 82% CMEs: 76%
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

8. Cross-Correlation plot of electrons and protons
Good correspondence between the electron and proton signatures of the same eruptive event:
e-p pair is performed under the condition for the same solar origin
small sample (172 events (SC23) & 93 events (SC24)) due to the fewer proton cases observed
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

9. correlation with flare class
SC23
SC24 k k k k
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10. correlation CME speed SC23 SC24 k k k k
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11. We aim to finally bridge this gap
Radio Emission Signatures Catalog
Motivation
The radio emissions considered as the signatures of in situ observed particles are always compared to the occurrences and peak intensities of protons and not to electrons
(e.g. Kahler, 1982; Chertok, 1990; Miteva, Klein, Samwel, …et al., 2013;
Miteva, Samwel, Krupar., 2017)
We aim to finally bridge this gap
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

12. Sources Radio Emission Signatures Catalog Radio observatory
frequency range, MHz
Data link
Ondrejov
800–5000
e-Callisto/Phoenix
10–5000
HiRAS
25–2500
Culgoora
18–1800
Green Bank
5–1100
Radio Monitoring
0.02–1000
ARTEMIS
20–600
IZMIRAN
25–270
Bruny Island
6–62
Wind/WAVES
0.02–14
STEREO/WAVES
0.02–16
RSTN (Sagamore Hill,
Palehua, Learmonth, and San Vito)
245, 410, 608, 1415, 2695, 4995, 8800, & 15400
ftp://ftp.ngdc.noaa.gov/STP/space-weather/solar-data/solar-features/solar-radio/rstn-1-second/
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

13. Radio Emission Signatures Catalog
Disclaimer: The radio catalog is still under construction!
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14. Preliminary results: Analysis of RSTN observatory reports as provided by SWPC (1997–2017)
Increasing trend of the Pearson correlation coefficients with the increase of the radio emission frequency of the electron-related flare, apart from the 15.4 GHz.
The correlations for the 2695–8800 MHz emission are statistically larger compared to the cases when GOES SXR flare class and CME projected speed is considered.
The differences between low (245 MHz) and higher frequencies (2695–8800 MHz) are statistically significant.
The trend is kept when the correlations are done both for low and high energy electron fluxes
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

15. Preliminary results (for both catalogs)
Miteva R., Samwel S.W., Danov D., “Catalogs of Solar Energetic Electrons and Their Radio Emissions in Solar Cycles 23 and 24”, Proceeding of the Fourteenth International Scientific Conference Space, Ecology, Safety SES 2018.
Ongoing and Future Work
Continue compiling both ACE/EPAM electron event catalog and Radio emission signature catalog
Perform Statistical analysis of the solar energetic electron events and their solar origin, in addition to the corresponding radio signatures .
Our results will be freely released to the community following their perspective publications
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria

16. Acknowledgement
SCOSTEP VarSITI scientific program under ISEST/Minimax24 with the project
‘Solar energetic electrons and radio emission signatures’
(Variability of the Sun and Its Terrestrial Impacts:
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17. Thank You
VarSITI Closing Symposium, June 10-14, 2019, Sofia, Bulgaria