1. Solar energetic particles and associated phenomena in radio and EUV wavelengths
R. Miteva1,
K.-Ludwig Klein1, Ines Kienriech2,
Astrid Veronig2 and Susan W. Samwel3
1 LESIA-Paris Observatory, CNRS, Meudon, France
2 IGAM/Institute of Physics, University of Graz, Austria
3 National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt
9th European Space Weather Week, 08–Nov–2012, Brussels, Belgium

2. Outline How to explain SEP events with parent activity far from the
source
surface
IP magnetic
field line
(Parker spiral or ICME?)
CME
How to explain SEP events with
parent activity far from the
nominal magnetic connection
(W50)?
flare
Radio emission
signatures for: shock waves,
trapped and escaping electron
beams
EUV emission
propagating large-scale
disturbances in the corona
SEPs
in situ solar energetic particles,
particles/(cm2 sr s MeV)

3. Data sample: SEPs Data selection deka-MeV protons (1997–2006)
• Cane et al (~25 MeV)
→ peak differential intensity,
Jp (cm2 s sr MeV)–1
• All SEP events are associated with
flares (X and M-class) and CMEs!
~ 100 western SEPs
(Miteva et al., Sol. Phys., accepted)
~ 50 eastern SEPs
(Miteva et al., CEAB, in progress)

4. Correlation: SEPs and flares/CMEs
Parent solar activity
Solar flares
X- and M-class (GOES 1-8 Å channel)
Solar Geophysical Data reports
→ SXR peak flux (Wm–2)
Coronal mass ejections (CMEs)
SOHO/LASCO C2
CDAW catalogue
→ on-sky projected speeds (kms–1)
→ No preferential particle accelerator (flare vs. CME)
can be identified from correlation studies!
open circles – Eastern SEPs
filled circles – Western SEPs

5. SEPs and radio signatures
GOES
(1–8 Å)
HiRAS
Culgoora
Ondrejov
Potsdam
ARTEMIS
IZMIRAN
Learmonth
Wind/
WAVES
Radio signatures
• from (all) ground-based radio
stations + Wind/WAVES satellite
• from observatory reports
IV: trapped electrons
dm/m-λ (3GHz–30 MHz)
Topic: statistical study on the temporal association between SEPs and radio signatures in the corona and IP space
during 23rd solar cycle
(1997–2006)
II: shocks
DH/km (30 MHz–20 kHz)
III: electron
beams

6. SEPs and radio bursts Here: a statistical study of
Earlier works (incomplete list!)
SEPs – m & DH type II bursts (signatures for shock wave)
Kahler (1982); Cliver et al. (2004); Gopalswamy et al. (2002, 2008)…
SEPs – m & DH type ‘normal’ III and III-L bursts (signatures for electron beams)
DH III-L (long-duration): Cane et al. (2002…), MacDowall et al. (2003, 2009), Cliver & Ling (2009),
Gopalswamy & Mäkelä (2010)…
SEPs – type IV bursts (signatures for trapped electrons)
Kahler (1982)
Here: a statistical study of
SEP–radio signatures of type II, III, IV
in dm-, m- and DH/km-wavelengths
with origin at E vs. W heliolongitudes
using dynamic radio spectra
and observatory reports
Miteva et al., CEAB, in preparation

7. Association rates: SEPs–radio bursts
E vs. W-longitudes
(dm-II → intrinsically rare feature!)
m-II → 90 % vs %
DH/km-II → % vs %
dm-III → 15 % vs %
m-III → % vs %
DH/km-III → all all
dm-IV → 48 % vs %
m-IV → 73 % vs %
(DH-IV → intrinsically rare feature!)
black – dynamic radio spectra
dark gray – observatory reports only or uncertain
light gray – data gap

8. Preliminary results: time offset
Time offset (definition)
Time at SXR max (SGData reports)
– time at 245 MHz (RSTN)
negative values: radio emission starts before the SXR max (i.e., in impulsive phase)
positive values: after
Analyzed events < 60 %
Results (single frequency data):
metric wavelength radio emission
starts in the impulsive flare phase
(future work: to extend the analysis to lower frequencies)
Results (radio spectra of type III bursts):
electrons accelerated in the corona can escape into IP space
→ flare contribution to SEPs!

9. Association rates: SEPs–EIT signatures
SOHO/EIT disturbances (Thompson & Myers 2009 catalog, Jan/1996 – Jun/1998 )
Preliminary results
• Western SEP events
Yes: 40% No: 13% uncertain: 47%
• Eastern SEP events
Yes: 42% No: 2% uncertain: 56%
• All SEP events
Yes: 40% No: 10% uncertain: 50%
Topic: statistical study on the temporal association between SEPs and EIT signatures of large-scale coronal
disturbances during 23rd solar cycle

10. Summary Radio signatures EIT signatures All cases:
• show electron acceleration in the
corona (radio)
• start in general during impulsive
flare phase
• have DH III (escape of electrons
to IP space)
• DH type II appears as a less typical
counterpart of SEP events, especially
in the western hemisphere, than
generally thought
EIT signatures
Association rates SEPs–EIT `waves’:
• EIT `waves’ candidates: ~40%
• No association: ~10%
• Virtually all E-events have EIT `waves’
• uncertain cases: ~50% !
(work in progress)

11. Discussion Application to space weather predictions
• Similar correlation coefficients between the peak SEP intensity and the parameters characterizing flare strength and CME projected speed
• Radio emission gives information on particle confinement or escape to IP space
• Confined particles: no m/DH radio and no SEP events (Klein et al. 2010, 2011)
• SEP events are accompanied always by m & DH radio emission
(present work, see Cane et al for DH radio)
• Tendency for the meter wavelength radio burst emission to start
during the flare impulsive phase
• Only ~50 % of the W-events have type II shock signature vs. ~85 % of the E-events
• EIT `waves’ signatures are promising candidate to connect eastern activity with
SEPs at Earth (see case studies, Krucker et al. 1999, Torsti et al. 1999)