1. The Terrestrial System under Super-CME Conditions George Siscoe Boston University
Main Theme: Three Worlds of Super-CMEs
At home
Birth, development, and release
At play
Acceleration, propagation, in-transit evolution
At work
Making superstorms
Subtheme: Super-CMEs are rare and weird like natural wonders
Epitomes of explosive phenomena in the local cosmos
Hurricanes of space weather
Radical transformers of magnetosphere coupling from solar wind dominated to ionosphere dominated

2. Super-CMEs at Home Birth, Development, and Release
Relation to active region, prominences, and “sigmoids”
Illustrated by event on November 4, 2001
Continuum
Magnetogram
H alpha
Soft X-ray
Composite

3. Photospheric Field Topology of Titov & Démoulin 1999 Model
upper
separatrix
upper
separatrix
lower
lower
separatrix
Basic topology of twisted magnetic configurations in solar flares
Astronomy and Astrophysics, 351, pp , 1999
upper
separatrix

4. Relation to magnetic arcades Illustrated by Bastille Day event

5. Release Mechanisms Flux Cancellation Breakout Terry Forbes
Spiro Antiochos

6. Conditions at Eruption

7. Observable Implication of CME Models (Crooker, 2005)
FLUX-CANCELLATION MODEL
Dipolar fields reconnect
Leading field matches dipolar component
BREAKOUT MODEL
Quadrupolar fields reconnect
Leading field opposes dipolar component
Taken at face value, imprint of dipolar component on leading field and leg polarity favors streamer over breakout model by ~80%.

8. Super-CMEs at Play Acceleration, propagation, in-transit evolution50
100
150
200
250
500
750
1000
1250
1500
Jie Zhang data

9. Geometrical Dilation + Radial Expansion Phase
Three Phases of CME Expansion
CME
Geometrical Dilation +
Radial Expansion Phase
Inflationary
Phase
MHD simulation
Pete Riley
Sun
Pre-CME
Growth
Phase

10. Information on Interplanetary CME Propagation50
100
150
200
400
600
800
1000
1200
1400
Gopalswamy et al., GRL 2000: statistical analysis of CME deceleration between ~15 Rs and 1 AU
Reiner et al. Solar Wind : constraint on form of drag term in equation of motion
Gopalswamy, N. ; Lara, A. ; Lepping, R. P. ; Kaiser, M. L. ; Berdichevsky, D. ; St. Cyr, O. C Interplanetary acceleration of coronal mass ejections Geophys. Res. Lett. Vol. 27 , No. 2 , p. 145 (1999GL003639)
Velocity-distance relationship for the January 14, 2002 CME.
“On the Deceleration of CMEs in the Corona and Interplanetary Medium
deduced from Radio and White-Light Observations”
M. J. Reiner, M. L. Kaisert and J.-L. Bougeret, in Solar Wind 10, 2003.
drag  Cd ρ (V-Vsw)2 Standard Form
Observed

11. Information on CME Parameters at 1 AU
Vršnak and Gopalswamy, JGR 2002: velocity range at 1 AU << than at ~ 15 Rs
Owen et al. 2004: expansion speed  CME speed; B field uncorrelated with speed; typical size ~ 40 Rs
Lepping et al, Solar Physics, 2003: Average density ~ 11/cm2; average B ~ 13 nT
Accelerate
Decelerate
350
400
450
500
550
600 20 40 60 80
Vexp = Vcme – 71.61
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. A2, /2001JA000120, 2002
Influence of the aerodynamic drag on the motion of interplanetary ejecta
Bojan Vršnak
Hvar Observatory, Faculty of Geodesy, Zagreb, Croatia
Nat Gopalswamy
Department of Physics, Catholic University of America, Washington, D. C., USA
Characteristic magnetic field and speed properties of ICMEs and their sheath regions
M.J. Owens, N.U. Crooker, G. Siscoe and C. Pagel
Center for Space Physics, Boston University, Boston, Massachusetts.
P.J. Cargill

12. Analytical model of CME Acceleration and Propagation
Generalized buoyancy
Elliptical cross section
Variable drag coefficient
Satisfies Gopalswamy template
Satisfies Reiner template
Virtual mass
Comparison with MHD simulation 50
100
150
200
400
600
800
1000
1200
1400
Gopalswamy et al.
Variable CD
Fixed CD
Velocity (km/s)
Distance from the Sun (Rs)
Circular CME 10 20 30 40 50
100
200
300
400
Velocity (km/s)
Distance from Sun (Rs)
MHD Simulation
Analytical
1.5 2
2.5 3
3.5 4
4.5 5
200
400
600
800
1000
Acceleration (m/s/s)
Distance from Sun Center (Rs)
Virtual Mass
No Virtual Mass
drag  Cd ρ (V-Vsw)2 Standard Form
Observed
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. A2, /2001JA000120, 2002
Influence of the aerodynamic drag on the motion of interplanetary ejecta
Bojan Vršnak
Hvar Observatory, Faculty of Geodesy, Zagreb, Croatia
Nat Gopalswamy
Department of Physics, Catholic University of America, Washington, D. C., USA
Characteristic magnetic field and speed properties of ICMEs and their sheath regions
M.J. Owens, N.U. Crooker, G. Siscoe and C. Pagel
Center for Space Physics, Boston University, Boston, Massachusetts.
P.J. Cargill

13. Predictability (Crooker)50
100
150
200
250
500
750
1000
1250
1500
from Crooker, 2004
Cloud axis
Aligns with filament axis (low) and HCS (high)
Directed along dipolar field distorted by differential rotation
Leading field
Aligns with coronal dipolar field (high)
Application
First part predicts the rest (Chen et al., 1997)
Cloud axis orientation, Fair
28/50 (56%) align within 30° of neutral line [Blanco et al., 2005]
Leading field, Good
33/41 (80%) match solar dipolar component with 2-3 year lag [Bothmer and Rust, 1997]
28/38 (74%) from PVO match [Mulligan et al., 1998]

14. CME Propagation Models50
100
150
200
250
500
750
1000
1250
1500
Gopalswamy
Template
Empirical model of CME deceleration (Gopalswamy et al., 2000)
Analytical model of CME propagation (Siscoe, 2004)
Numerical simulation 0.5 to 50 AU (Odstrcil et al., 2001)
Numerical simulation 1 Rs to 1 AU with two codes (Odstrcil et al., 2002) 50
100
150
200
400
600
800
1000
1200
1400

15. Super-CMEs at Work Making Superstorms
Dynamic Pressure (nPa)
Psw distributions in CIRs and CMEs (Lindsay et al., 1995)
Ey distributions in CIRs and CMEs (Lindsay et al., 1995)
GeoImpact of CMEs (Gosling, 1990)
Ionosphere
Dominated
Solar Wind

16. The Terrestrial System under Super-CME Conditions
Vasyliunas Dichotomization
Solar wind dominated
Ionosphere dominated
Global force balance via Chapman-Ferraro current system
Dst responds to ram pressure
Global force balance via region 1 current system
Neutral flywheel effect
No (direct) Dst response to ram pressure
Magnetopause erosion
Transpolar potential saturation (TPS)
Equivalent to ionosphere dominated regime
Evidence for TPS and the Hill model parameterization

17. Vasyliunas Dichotomization
Vasyliunas (2004) divided magnetospheres into solar wind dominated and ionosphere dominated depending on whether the magnetic pressure generated by the reconnection-driven ionospheric current is, respectively, less than or greater than the solar wind ram pressure. The operative criterion is
oPVAε ~ 1
P = ionospheric Pedersen conductance
VA = Alfvén speed in the solar wind
ε = magnetic reconnection efficiency
Key Point
By this criterion, the standard magnetosphere is solar wind dominated; the storm-time magnetosphere, ionosphere dominated.

18. Pertinent Properties of the Standard Magnetosphere
Chapman &
Ferraro, 1931
Pertinent Properties of the Standard Magnetosphere
Chapman-Ferraro Current System
Midgley &
Davis, 1963 x z
ICF = BSS Zn.p./o
 3.5 MA
C-F compression
= 2.3 dipole field
2x107 N

19. Ram Pressure Contribution to Dst
A Chapman-Ferraro property
April 2000 storm
Huttunen et al., 2002
GOES 8
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. A12, 1440, doi: /2001JA009154, 2002
April 2000 magnetic storm: Solar wind driver and magnetospheric
response
K. Emilia J. Huttunen,1 Hannu E. J. Koskinen,1,2 Tuija I. Pulkkinen,2 Antti Pulkkinen,2
Minna Palmroth,2 E. Geoffrey D. Reeves,3 and Howard J. Singer4
Psw compresses the magnetosphere and
Increases the magnetic field on the dayside.
Chapman-Ferraro Compression

20. Interplanetary Electric Field Determines
Transpolar Potential
A magnetopause reconnection property 5 10 15 20
100
200
300
400
500
Transpolar Potential (kV)
Ey (mV/m)
Magnetopause reconnection
Equals transpolar potential
Transpolar potential varies linarly with Ey (Boyle et al., 1997)
Magnetosphere a voltage source as seen by ionosphere B E V
Burton, R. K., R. L. McPherron, and C. T. Russell, The terrestrial magnetosphere: A half-wave rectifier of the interplanetary electric field, Science, 189, 717, 1975.
Burton, R. K., R. L. McPherron, and C. T. Russell, An empirical relationship between interplanetary conditions and Dst, J. Geophys. Res., 80, , 1975.
Kan, J. R., and L. C. Lee, Energy coupling function and solar wind-magnetosphere dynamo, Geophys. Res. Lett, 6, , 1979.
Boyle, C. B., P. H. Reiff, and M. R. Hairston, Empirical polar cap potentials, J. Geophys. Res., 102, , 1997.
IMF = (0, 0, -5) nT

21. Solar Wind Dominated Magnetosphere
Summary
Psw compresses the magnetospheric field and increases Dst.
Ey increases the transpolar potential linearly.
Magnetosphere a voltage source
Key Point
Field compression and linearity of response to Ey hold for only one of the two modes of magnetospheric responses to solar wind drivers—the usual one.

22. Then Came Field-Aligned Currents
Iijima &
Potemra, 1976
Region 1
Region 2
Atkinson, 1978
R 1
C-F
Tail
3.5 MA
5.5 MA
1 MA/10 Re
Total Field-Aligned Currents
for Moderate Activity
(IEF ~1 mV/m)
Region 1 : 2 MA
Region 2 : 1.5 MA
Question: How do you self-consistently
accommodate the extra 2 MA?

23. Answer: You Don’t. You replace the Chapman-Ferraro current with it.
IMF = (0, 0, -5) nT

24. Region 1 Force on Earth Region 1 Current Contours Streamlines
5x106 N
We move now to slides dealing with the region 1 currents. They are taken from an ISM run in which the IMF is straight south. This slide gives a view of the northern polar cap in which parallel current is depicted in colored contours (blue = negative, tan = positive) and a set of current streamlines is shown in red. The symmetrical pair of closed contours of strong parallel current is the ionospheric expression of the region 1 current. The red current streamlines will now tell us (in the next slide) where the region 1 currents go in the magnetosphere. In particular, we are interested in where they close. One school of though says that they close in the cross-tail current sheet, another school says on the high-latitude magnetopause.
IMF = (0, 0, -5) nT

25. Impact of Region 1 Currents on Understanding
Solar Wind-Magnetosphere Coupling
Summary
Ionosphere and solar wind in “direct” contact
Solar wind can pull on ionosphere as well as push on earth.
Region 1 currents can usurp Chapman-Ferraro currents.
Influence of ionosphere coupling increases relative to Chapman-Ferraro coupling as interplanetary electric field (Ey) increases.
Key Point
During major magnetic storms, this leads to an
ionosphere dominated magnetosphere

26. What does this mean?
It means that whereas the standard magnetosphere interacts with the solar wind mainly by currents that flow in and on the magnetosphere,
the storm-time magnetosphere interacts with the region 1 current system that links the ionosphere to the solar wind in the magnetosheath and the bow shock.

27. Transpolar Potential Saturation
IMF = 0
Chapman-
Ferraro
Region 1
IMF Bz = -30 10 20 30 40 50
100
150
200
250
300
350
Ey (mV/m)
Transpolar Potential (kV)
PSW=10
Baseline (PSW=1.67, Σ=6)
Σ=12
Linear regime (small ESW) 6 1 . 57 / sw P E H = F
Saturation regime (big ESW)

28. And most important
Bow Shock
Streamlines
Region 1
Current
Reconnection
Ram
Pressure
Cusp
Region 1 current gives the J in the JxB force that stands off the solar wind
And communicates the force to the ionosphere
Which communicates it to the neutral atmosphere as the flywheel effect
Winds in the high-latitude lower thermosphere: Dependence on the interplanetary magnetic fieldAuthors: Richmond, A. D.; Lathuillère, C.; Vennerstroem, S.Journal: Journal of Geophysical Research (Space Physics), Volume 108, Issue A2, pp. SIA 10-1, CiteID 1066, DOI /2002JA (JGRA Homepage)Publication Date: 02/2003
Richmond et al., 2003

29. Evidence of Two Coupling Modes
Transpolar potential saturation
Instead of this
You have this
No dayside compression seen at synchronous orbit
Hairston et al., 2004 5 10 15 20
100
200
300
400
500
Transpolar Potential (kV)
Ey (mV/m)
Cahill & Winckler, 1999
Dipole Field
April 2000 storm
Huttunen et al., 2002
GOES 8
Saturation of the ionospheric polar cap potential during the October-November 2003 superstorms
Marc R. Hairston, Kelly Ann Drake, Ruth Skoug
The geostationary field during dayside erosion events : A joint Wind, ACE, and GOES studt, Muehlbachler st al., JGR, A12, 2003
Foster, Coster, et al, Stormtime observations of the flux of plasmaspheric ions to the dayside cusp/magntopause, GRL, 31, 2004.

30. To Resume Transpolar potential saturation
No dayside compression seen at synchronous orbit
No compression term (b) in the Burton-McPherron-Russell equation: dDst*/dt = E – Dst*/ Dst* = Dst - b√Psw
Instead of this
You have this
Ring current model fits storm main phase better without pressure correction
Possibly related:
Large parallel potential drops
Sawtooth events
Lee et al., 2004
b = 11.7
McPherron, 2004
Jordanova, 2005
Saturation of the ionospheric polar cap potential during the October-November 2003 superstorms
Marc R. Hairston, Kelly Ann Drake, Ruth Skoug

31. The Bimodal Magnetosphere Summary
Quiet Magnetosphere
Dominant current system Chapman-Ferraro (Region 1 lesser)
Magnetopause current closes on magnetopause
Magnetopause a bullet-shaped quasi-tangential discontinuity
Transpolar potential proportional to IEF
Solar wind a voltage source for ionosphere
Compression strengthens dayside magnetic field
Minor magnetosphere erosion
Main dynamical mode: substorms
Force transfer by dipole Interaction
Superstorm Magnetosphere
Dominant current system Region (no Chapman-Ferraro)
Magnetopause current closes through ionosphere and bow shock
Magnetopause a system of MHD waves with a dimple
Transpolar potential saturates
Solar wind a current source for ionosphere
Stretching weakens dayside magnetic field
Major magnetosphere erosion
Main dynamical mode: storms
Force transfer by ion drag
Dichotomization, transpolar potential saturation, no Dst response
to ram pressure, magnetopause erosion, neutral flywheel effect all part of one story.

32. THE END
Thank You

33. You have this Cahill & Winckler, 1999 45o 5 nT 0o 5 nT Dipole Field

34. Properties of Ionosphere-Dominated Magnetosphere
Region 1 Current System Fills Magnetopause
Region 1 Current
Contours