Laboratoire de Physique des Plasmas

SOLAR EVENTS TOWARDS THE EARTH IN 2002

B.Schmieder (1), N. Cornilleau-Wehrlin (1), K. Bocchialini (2), M. Menvielle (3), A. Chambodut(4), 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)

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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 eventsESWW12 Ostende November 2015

Starting point #1 SSC May 23 2002 at 10:18 UT

By using the geomagnetic indices (Dst, SYM-H…)

SSC Storm Sudden Commencement = compression of the magnetosphere indicating the arrival of the shock. Date; Amplitude; Quality (23-05-2002 10:18; 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 surfaceValue of the minimum; Classification (-109; Intense Storm )

nT

SSC day of the year 142 : 22 May

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Starting point # 2 Sun: search of CME SOHO 22 05 2002 01:13 UT

AR 9948

EIT : 30.4 nm EIT : 19.5 nmLocation (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 ) ESWW12 Ostende November 2015

X ray Flux measured by GOES

W/m

2C Class

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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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Interplanetary Medium at L1 : ACE Satellite

Characteristics of the observations: ICME (Interplanetary CME) or NOT ?

t _sscICME : increase of V t1: shockt2 : start of the ICME t3 : end of the ICME

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Ionospheric radars SuperDARN : Polar Cap potential through the

pole

SSC

Maximum value of the PCP (85-95)Maximum time after the SSC (01:15)Nb of points (quality) (100-200)

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Global convection maps

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) ESWW12 Ostende November 2015

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 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)ESWW12 Ostende November 2015

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

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Comparison SSC at L1Characteristics at L1

Nb Mean SSC amplitude > 35 nT

Large Dst -200<.<-100 nTIntense storms

Medium Dst-100<.< -50 nTModerate storms

Weak Dst> -50 nTWeak storms

ICME 17 7** 8** 4 5

CIR-SIR * 4 0 0 0 4

OTHER (SW) 4 0 0 0 4

UNCLEAR ICME 6 1 0 3 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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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 6CMEN 5 5 2 CMEN,H ; 3 sources 13 +1 14CIR -SIR 5 5No ID 5 5Total 11 14 10 35

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With 4 false detections (ICME not detected in L1) 26 Halo CMEs only 16 impacted the Earth with SSCs.

25

Propagation speed CME at L1

• After identification, drag coefficient for a drag model

Coefficient(10-7 km-1)

0.1-0.5

0.5-1.0 1.0-1.5 >1.5

Case Number

10 8 4 1

Only 23 cases of ejections have been considered.No correlation with the speedMay be some correlation with the mass

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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: variable

• 35 SSC• 51 CME

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• 25 from the 35 SSC associated with CME and identified solar source; 4 CIR; 5 unclear

• 11 SSC clear identified with one ICME• 14 of the 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)• Speed model have to be upgraded

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Conclusions and perspectives (2)

Atelier Météo Meudon juin 2015 NCW

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 2002 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

Laboratoire de Physique des Plasmas

Thank for your attention

Acknowledgment: PNST .

Vitesse de propagation CME vers L1

• Après identification, calcul du coefficient de freinage dans le modèle avec freinage:

Coefficient(10-7 km-1)

0.1-0.5

0.5-1.0 1.0-1.5 >1.5

Nb cas 10 8 4 1

Le calcul n’a pu se faire que sur 23 casPas de corrélation trouvée avec la vitesse d’éjection regarder la masse

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