1. Solar Events towards the Earth in 2002
B.Schmieder
K. Bocchialini (2), M. Menvielle (3), A. Chambodut(4), , N. Cornilleau-Wehrlin (1)D. Fontaine(1),B. Grison (5),C. Lathuillère (6), A. Marchaudon(7), M. Pick(8), F. Pitout(7), S.Régnier(9),
N. Vilmer (8), Y. Zouganelis(1)
ESWW12 Ostende November 2015

2. Back and Forth method
We propose a statistical analysis covering one year (2002) to investigate the link between
SSC (Storm Sudden Commencement), detected by the magnetic observatories on the ground and
the Coronal Mass ejection (CME).
propagation in a time window ~1 to 5 days (ballistic propagation ballistic between 300 km/s and 1500 km/s)
The method is back and forth to find the correct association of events (step 1, step 2, step 3, step1…)
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3. Some results obtained in one year of measurements (2002) during the cycle 23 maximum
From
35 SSC identified in 2002
51 CME with an identified solar source (if no halo CME has been identified we search for a partial CME)
Characterisation of the perturbation ICME recorded at L1 before the SSC
Geomagnetic indices
Ionosphere (Super Darn, Thermosphere CHAMP)
Only a few of in situ magnetosphere observations (Cluster operated until July 2002)
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4. Starting point #1 SSC May 23 2002 at 10:18 UT By using the geomagnetic indices (Dst, SYM-H…)
SSC day of the year 142 : 22 May
SSC Storm Sudden Commencement = compression of the magnetosphere indicating the arrival of the shock. Date; Amplitude; Quality ( :18; 78 nT; 2) Dst (hour) et SYM-H (1 mn) variations related to the annular magnetospheric currents of the horizontal magnetic component at the Earth surface Value of the minimum; Classification (-109; Intense Storm )
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5. Starting point # 2 Sun: search of CME SOHO 22 05 2002 01:13 UT
EIT : nm EIT : 19.5 nm
Location (881,-319 arcsec) and characteristics of the source region (AR, Filament,Flare)
LASCO/SOHO CME : speed , altitude, acceleration , time of exit of the field of view (150 4km/s, 28 Rs, -10.4, 06:50 UT )
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6. Interplanetary Medium at L1 : ACE Satellite
Starting point #3
Interplanetary Medium at L1 : ACE Satellite
Characteristics of the observations:
ICME (Interplanetary CME) or NOT ?
t _ssc
ICME : increase of V
t1: shock
t2 : start of the ICME
t3 : end of the ICME
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7. Ionospheric radars SuperDARN : Polar Cap potential through the pole
Global convection maps
Ionospheric radars SuperDARN : Polar Cap potential through the pole
Maximum value of the PCP (85-95)
Maximum time after the SSC (01:15)
Nb of points (quality) ( )
SSC
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8. Thermosphere : Measurements of the satellite CHAMP (400 km)
The measurements are normalised by a quiet time model
Coef. = 2 => augmentation de 100% of the density.
Weak signal for Dst >-15 otherwise the density increases by a factor 1.5 to 2.5 (good agreement with the study of Krauss et al (2015)
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9. Characteristics of 35 SSC sources: 51 CME and solar source
Type of SSC origin
1 Solar source
multi sources
No solar souce
Total
CMEH 6
CMEN 5
2 CMEN,H ; 3 sources
13 +1 14
CIR -SIR
No ID 11 10 35 25
With 4 false detections (ICME not detected in L1)
26 Halo CMEs only 16 impacted the Earth with SSCs .
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10. Comparison SSC at L1
Characteristics at L1 Nb
Mean SSC amplitude > 35 nT
Large Dst
-200<.<-100 nT
Intense storms
Medium Dst
-100<.< -50 nT
Moderate storms
Weak Dst
> -50 nT
Weak storms
ICME 17
7**
8** 4 5
CIR-SIR *
OTHER (SW)
UNCLEAR ICME 6 1 3
Total
31 ***
* Co rotating interaction region (SIR visible in more than one rotation)
** Only two events with large amplitude (> 35 nT) correspond to large Dst (not link to the shock but to the compression)
*** 31 for 35 SSC because 4 pairs of sscs
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11. Conclusions and perspectives (1)
From the Sun to the Earth
Association CME – SSC:
One year of data during the solar maximum;
Relatively low number for a good statistic
Results: surprising.. about the halo CME…
35 SSC
51 CME (26 halo + 25 non halo)
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12. Conclusions and perspectives (2)
35 SSC
25 SSC associated with CME and identified solar source; 4 CIR; 5 unclear
11 SSC clear identified with one CME
14 25 SSC are due to multiple CMEs (can explain the « unclear » case at L1)
L1 : 19 ICME identifiable
5 SSC with no identified solar source (no CME neither CIR)
Bocchialini et al 2016 (in preparation) – web site
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13. Conclusions and perspectives (3)
The 2002 data are in a data base (1996_2007) at ias.u-psud.fr which should publish in a paper (in preparation)
We need to increase the statistic base:
To complete the results in with results of other papers.
To use a data base
To complete with data of new satellites in operation since 2007 (STEREO..)
Future study : SSC without CME
Atelier Météo Meudon juin NCW

14. Thank for your attention
Acknowledgment: PNST .

15. Vitesse de propagation CME vers L1
Après identification, calcul du coefficient de freinage dans le modèle avec freinage:
Coefficient
(10-7 km-1)
>1.5
Nb cas 10 8 4 1
Le calcul n’a pu se faire que sur 23 cas
Pas de corrélation trouvée avec la vitesse d’éjection  regarder la masse
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16. Back and Forth method
It is a classical method to follow a solar event towards the Earth and see its geoeffectiveness.
Many case studies exist (i.e. Hanuise et al, 2006), some statistics have been performed selecting only halo CMEs (Gopalswamy et al, 2009, Cid et al, 2012)
We propose a statistical analysis covering one year (2002) to investigate the link between SSC (Storm Sudden Commencement), detected by the magnetic observatories on the ground and the Coronal Mass ejection (CME).
The method is back and forth to find the correct association of events
ESWW12 Ostende November 2015

17. X ray Flux measured by GOES
C Class
W/m2
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18. Radio bursts in the Solar Wind at L1
Type II: associated with a shock
Type IV: associated by a CME, important ejection
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19. Some results Association YES/NOT with CME  SSC
propagation in a time window ~1 to 5 days (ballistic propagation ballistic between 300 km/s and 1500 km/s)
When there is an association, work on the model of propagation using a drag model. If you know the velocity at the starting point and the velocity at the arrival the drag coefficient Ss can be determined with more precision.
Using empiric models does not give better results
ESWW12 Ostende November 2015

20. Propagation speed CME at L1
After identification, drag coefficient for a drag model
Coefficient
(10-7 km-1)
>1.5
Case Number 10 8 4 1
Only 23 cases of ejections have been considered.
No correlation with the speed
May be some correlation with the mass
ESWW12 Ostende November 2015