2004 September 11 CAWSES Theme 2 Meeting, Beijing

Solar Sources of Geoeffective Disturbances

N. Gopalswamy

NASA/GSFC

Greenbelt, MD 20771

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Geoeffectiveness

• Ability to significantly disturb geospace

• Dst < -50

• SEP Ip > 10 pfu in the 10 MeV channel

• Arrival of plasmas, particles and electromagnetic radiation decide the lead times available

• Narrow down the solar events for space weather forecast purposes

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Geoeffective Solar Events

• Coronal Mass Ejections (severe geomagnetic storms, SEP events): most unpredictable

• High-speed Streams (mild, but numerous geomagnetic storms)

• Flares (prompt effects such as SID)

2004 September 11 CAWSES Theme 2 Meeting, Beijing

What In situ Observations tell us?

• CMEs bring strong magnetic fields

• Number of MCs ~ number of storms with Dst < -100 nT

• All IP shocks are CME-driven (ESP, SSC)

• Earth in CME related flows for about a third of the time during solar max

Gopalswamy et al., 2004Adv. Space Res.

2004 September 11 CAWSES Theme 2 Meeting, Beijing

TRANSIENT Flows at Earth

2 shock + sheath3 shock+Sheath+MC

4 MC Only (slow)

1 Shock only

Earth is embedded within one or the other of the above CME-related flows for ~ 35% Time during solar maxima and ~ 10% of the time during solar minima (Cliver et al. 2003)

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Solar Wind Magnetic Field1997 02 07 CME

0 20 40B nT5

Luhmann et al. 1999 (schematic)

%

OC

CU

RR

EN

CE

Wind Mag Clouds1996-2003

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Solar Sources of ICMEs

Only shock

Shock + ICME

Shock+ICME Interacting with Preceding CMEs

Sources ofIP shocks

Manoharan et al. 2004 JGR

Close to Disk Center (±30deg); Slight westward bias (Wang et al; Zhang et al)

2004 September 11 CAWSES Theme 2 Meeting, Beijing

CMEs REACHING THE HELIOSPHERE

Ulysses LASCO HL LASCO LL 1 AU

8 101 602 25

8% 4% (8%)w/o Backsided CMEs

~ a tenth of the CMEs produced at the Sun seem to reach far into the heliosphereThese are the ones that survive for long distances from the Sun

July 10 2000 – February 5, 2001 (7 months); Ulysses poleward of S60

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Special Populations (1-2)%

• Only a small fraction of all CMEs has significant influence on the heliosphere

• Halo CMEs – responsible for large geomagnetic storms

• Fast and wide CMEs responsible for accelerating electrons (radio bursts) and SEPs

• Fast & Wide Western CMEs produce high levels of SEP intensity at Earth

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Halos are similar to other CMEs:Wait for STEREO

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Halo CMEs

• Full halos (F)• Asymmetric Halo (A)• Partial halo (P)• The faint extension

on the opposite limb may be the CME-driven shock

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Halo CMEs are Faster on the Average

• Halo CMEs have an average speed of 1000 km/s

• Likely to be geoeffective if Earth-directed and posses southward B

• Likely to accelerate SEPs by driving shocks

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Fast and wide…

(47 deg non-halo)

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Metric Type II

IP Type II

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Speed, Width & Acceleration of DH CMEs

<V> = 1122 km/s <W> = 104 deg <a> = -6 m/s/s

- CMEs driving shocks in the near-Sun IP medium are faster and wider than regular CMEs- Tend to decelerate, probably due to coronal drag. (Gopalswamy et al., 2001 JGR )

2004 September 11 CAWSES Theme 2 Meeting, Beijing

CME Mass is also much higher

5.0x1015

<M>1.6x1016

1.5x1016<M> ~ 1.5x1015 g for all CMEs(Vourlidas 2004)

2004 September 11 CAWSES Theme 2 Meeting, Beijing

DH type II, FWFW, SEPs• Overall good correlation

because of physical relation (CMEshockparticles)

• DH is largest in number (Eastern Events included)

• Minor differences due to other parameters like Alfven speed

• Too many flares

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Problem Areas

• Halo CMEs without Geomagnetic Storms (Proper characterization; orientation of the magnetic field?)

• Fast and wide CMEs without particle acceleration (property of the ambient medium?) Use radio data (All large SEP events are associated with IP type II)

2004 September 11 CAWSES Theme 2 Meeting, Beijing

Working Group: Solar Sources of Geomagnetic Activity

Main Topics1. Solar sources: Coronal Mass Ejections, Coronal Holes, Large-scale Magnetic structures and boundaries, Polar magnetic fields2. Structure of the heliosphere and interplanetary transport of solar eruptions3. Solar energetic ions and electrons4. Geospace response to solar events

The Project TeamN. Gopalswamy (USA, Chair)B. V. Jackson (USA)V. Obridko (Russia)A. Prigancova (Slovakia)B. Schmieder (France)K. Shibasaki (Japan)D. Webb (USA, IAU Rep. )S. T. Wu (USA)M. Kojima (Japan)M. Zhang (China)….

ObjectivesTo understand how solar events such as CMEs and high speed streams impact the geospace- investigation of the underlying science- development of prediction/forecast models and necessary tools

MeetingsPreliminary meeting in China(before IAU Symposium Sep11-12 2004)Large meeting in 2005 (during the SCOSTEP Symposium)

WG formed during the ISCS meetingin Slovakia, June 2003

2004 September 11 CAWSES Theme 2 Meeting, Beijing

CAWSES Campaign(March 29-April 4, 2004)

Participants – Solar

SOHO/LASCO (N. Gopalswamy)HeI 10830 (J. Burkepile)H-alpha (B. Schmieder, Haimin Wang)ISOON (D. Neidig)Microwave (Shibasaki)IPS (Manoharan, Tokumaru)SXI (D. Biesecker)Metric (M. Akioka)Decametric (M. Kaiser, N. Gopalswamy)

CME list (11 CMEs)Flares

http://cdaw.gsfc.nasa.gov/CAWSESWhat Next?