1. Extreme CME Events from the Sun Nat Gopalswamy NASA/GSFC nat.gopalswamy@nasa.gov Extreme Space Weather Events (ESWE) workshop, Boulder, CO May 14-17, 2012

2. Extreme Event Event on the tail of the distribution An occurrence singularly unique either in the occurrence itself or in terms of its consequences Occurrence: CME Consequences: SEP events, magnetic storms Will use CME speed as the key parameter

3. Significant CMEs & their Consequences m2 – Metric type II MC – Magnetic Cloud EJ – Ejecta S – Interplanetary shock GM – Geomagnetic storm Halo – Halo CMEs DH – Type II at λ 10-100 meters SEP – Solar Energetic Particles GLE – Ground Level Enhancement Plasma impact Energetic electrons Energetic protons p<10 -4 p~0.3% Gopalswamy, 2006; 2010 Cycle 23 – 24 CMEs from SOHO/LASCO

4. Tail of the CME Distribution CategoryNumber of CMEs All identified CMEs18000 # CMEs with V ≥ 1000 km/s539 # CMEs with V ≥ 1500 km/s131 # CMEs with V ≥ 2000 km/s39 # CMEs with V ≥ 2500 km/s9 # CMEs with V ≥ 3000 km/s2 # CMEs with V ≥ 3500 km/s1 # CMEs with V ≥ 4000 km/s0

5. CME speed and in-situ shock association 100% 0% Type II Burst CMEs faster than 1000 km/s Had type II bursts extending below 1 MHz Originated from close to disk center Ended up with shocks surviving to 1 AU

6. AR Potential Field Energy ~ Free Energy ф = AR flux; A = AR area; E = AR Potential energy Free Energy ~ Magnetic Potential energy (Mackay et al., 1997) Free energy is > Mag PE by a factor 3-4 (Metcalf et al. 2005) Max potential energy during cycle 23 ~ 4 x 10 34 erg Max CME KE observed ~ 1.2 x 10 33 erg CME Speed limit  maximum energy that can be stored depending on A, B B < 6100 G; A < 5000 msh  E ~ 10 36 erg Livingston et al. 2006; Newton, 1955 Gopalswamy et al., 2010 E = ф 2 /(8πA ½ ) 1000 (1000, 3675) V = 675logE 33 + 1650

7. Max speed from mag PE V = 675logE 33 + 1650; E = ф 2 /(8πA ½ ) ф = BA E~10 36 or E 33 = 10 3  V = 3675 km/s Transit time = 11.3 h But there is the solar wind  longer transit time ~12.6 h (2005 Jan 20 CME had this speed; transit time was 34 h because the source was at W60)

8. Alfven Speed in the Source Region V A = 1500 km/s; L ~175,000 km  a ≤ 13 kms -2 ½ ρV 2 ≤ B 2 /8π  V ≤ V A  a ≤ V A /t A = V A 2 /L  (Vrsnak et al. 2007) V – CME speed VA – Alfven speed L – size of the eruptive structure

9. Initial Acceleration of CMEs Zhang et al., 2001; Vrsnak et al., 2007; Bein et al. 2011; Gopalswamy et al. 2012

10. Significant CMEs & their Consequences m2 – Metric type II MC – Magnetic Cloud EJ – Ejecta S – Interplanetary shock GM – Geomagnetic storm Halo – Halo CMEs DH – Type II at λ 10-100 meters SEP – Solar Energetic Particles GLE – Ground Level Enhancement Plasma impact Energetic electrons Energetic protons p<10 -4 p~0.3% Gopalswamy, 2006; 2010 Cycle 23 – 24 CMEs from SOHO/LASCO

11. Large SEP Events: Shock-driving CMEs 06:24 06:30 06:30 - 06:24 FR Core S S a bc 2005/01/15 Fast CMEs drive shocks Shocks accelerate particles Particles travel along interplanetary field line Particle radiation most hazardous in directly affecting astronauts, space technology Kahler, Hildner, & Van Hollebeke (1978)

12. Coronal Alfven Speed Height of shock formation Height of Particle release CMEs need to be superAlfvenic to drive a shock Shock formation typically happens close to the surface as indicated by the type II bursts Around the time of release of SEPs, CMEs reach a height of ~3.6 Rs, where the Alfven speed is ~600 km/s For Mach 2, the CME speed needs to be 1200 km/s Gopalswamy et al. 2012

13. SEP Producing CMEs The CMEs are very fast Almost all CMEs are halos or partial halos Halo CMEs are generally wide

14. CMEs are Efficient Accelerators Mewaldt, 2006 Typically about 10% of CME kinetic energy goes into SEPs Similar to flare energy Expect GLEs to be associated with energetic CMEs

15. Middle Atmosphere 0 20 40 60 80 100 Altitude (km) Troposphere Stratosphere Mesosphere Thermosphere Tropopause Stratopause Mesopause Particle radiation from the Sun can destroy ozone 1 MeV proton 100 MeV proton 10 MeV proton GOES provides Proton flux for >1 MeV to >100 MeV 1 GeV proton OZONE courtesy: C. Jackman

16. Seppälä et al. 2008 NOx Production due to Jan 2005 SEP Events

17. Cycles 21-24 233 large SEP events 1976 – 2012 March Carrington Event (Est. 2495 pfu) # SEP Events with intensity ≥F Cumulative Distribution of SEP Events from NOAA Proton Events List log (Ip) = - 9.08 + 3.7 log (V) - from cycle 23 SEP events Ip = >10 MeV proton intensity (pfu) V = CME speed For the Carrington event, transit time is known (17.5 h). Estimate V = 2356 km/s from ESA model Ip = 2495 pfu May not be an extreme SEP event but: Manchester et al. 2006: The model CME started out with ~4000 km/s and ended up having 2000 km/s at 1 AU (average speed: 3000 km/s)

18. Historical Fast Transient Events Cliver et al., 1990; Gopalswamy et al., 2005

19. Historical Fast Transit CMEs: KE Estimate SOHO CMEs 27.9 h 18.9 h 19.7 h 31.8 h V 1 Aug 4, 1972 14.6 h V=2854 km/s 2 Sep 1, 1859 17.5 h V = 2356 km/s 1.2x 10 33 erg T = ab V + c; a = 151.002, b = 0.998625, and c =11.5981 (ESA model) Cycle 24 CMEs: Shock Transit time ≥35 km/s Gopalswamy et al. 2005

20. CMEs Producing Magnetic Storms The CMEs are very fast (projected speed ~1041 km/s) Almost all CMEs are halos or partial halos (92%)

21. Geomagnetic Storm and CME parameters Dst [nT] V MC B z [10 4 nT km/s] Gopalswamy 2008 Dst = – 0.01VB z – 32 nT The high correlation suggests That V and Bz are the most Important parameters ( - Bz is absolutely necessary) V and Bz in the IP medium are related to the CME speed and magnetic content

22. Origin of V and B Dst = – 0.01VB z – 32 nT Solar Wind speed CIR Speed CME speed Alfven waves CIR: Amplified Alfven waves ICME: Sheath & Flux rope Heliospheric Mag Field Active Region Mag Field Active Region Free energy

23. V and Bz in CIRs and ICMEs Cycle 23 Storms: Major (Dst < -100 nT): 86% due to CMEs; 14% CIRs No CIR storm with Dst < -130 nT Gopalswamy, 2008 V = 2000 km/s, Dst = -1650 nT  Bz = -81 nT Carrington Event: VBz = 1.6 10 5 nTkm/s

24. Occurrence Rate of mag. storms Cumulative Distribution Occurrence Frequency Carrington Event # Events with intensity ≥|Dst| See also Riley, 2011

25. Geoeffective & SEP-producing CME Sources CMEs need to arrive at Earth CMEs must contain Bz South Similar to MC and Halo CME sources CMEs need to drive shocks Source region needs to be magnetically connected to Earth Many double-whammy events Carrington Event N20W12

26. Super flares from Solar-type Stars Super flares: Flares with energy at least 100 times that of a solar flare of importance 2 [Schafer, King and Deliyannis, 2000] The frequency of super flares is likely to be zero on the Sun based on 9 super flares in stars of spectral type F8 – G8 (main sequence stars) Using Kepler observations, Maehara et al. (2012) found 365 super flares from 148 G-type main sequence stars (including 101 stars with rotation period >10 days)

27. Typical Super Flare Observed by the Kepler Mission Brightness of a star and a flare Time (day) Total energy ~ 10^35 erg Maehara et al. (2011) Courtesy: K. Shibata

28. Solar and Stellar Super Flares Different? Maehara et al. (2012) concluded that super flares with energy ~10 35 erg may occur once in 5000 years (may also occur with a similar frequency on the Sun) Absence of world-spanning aurorae in historical records (Wolff et al. 2012) Many F and G main-sequence stars have close Jovian planetary companions  different type of magnetic reconnection: star field tangled by the Jovian planet field (Rubenstein and Schaefer, 2000) What type of CMEs?

29. Summary The extreme CMEs can be related to the available free energy in active regions, which in turn depends on the strength of the AR field and AR size Using the highest observed values, one can get up to a CME speed of ~7000 km/s SEP and Dst consequences depend critically on the CME structure (Shock for SEPs, BzS for Dst), but also on the CME kinematics Super Flares from solar-like stars are worth studying: different type of magnetic reconnection possible

30. Max speed from mag PE V = 675logE 33 + 1650; E = ф 2 /(8πA ½ ) ф = BA E~10 36 or E 33 = 10 3  V = 3675 km/s If all the energy went into a single CME, V~14,000 km/s (for M ~10 18 g) Halloween 2003 period: 5 – 26% of free energy went into the CME kinetic energy  CME speed is expected to be ~3200 to 7000 km/s

31. CMEs and Flares

33. V A = 2.18 × 10 6 n −1/2 B V = 3675 km/s; n = 10 9 cm -3 B =