1. Predicting the Probability of Geospace Events Based on Observations of Solar Active-Region Free Magnetic Energy
Dusan Odstrcil1,2 and David Falconer3,4
1George Mason University, Fairfax, VA, 2NASA/GSFC, Greenbelt, MD
3University of Alabama, Huntsville, AL, 4NASA/MSFC, Huntsville, AL
MURI/NADIR Workshop Boulder, CO October 25-26, 2011

2. Lead Times in Forecasting
Observation of heliospheric disturbances at L1
Lead time: ~30-50 min
Observation of coronal eruptions
Lead time: ~1-3 days
Observation of solar active regions
Lead time: ~3-5 days

3. Photospheric Magnetic Field CME Probabilistic Model
CAR=E26S10
PCME = 16%
RCME = 470
VCME = slow
CAR=E13S10
PCME = 15%
RCME = 490
VCME = slow
CAR=E00S10
PCME = 13%
RCME = 510
VCME = slow
CAR=W13S10
PCME = 17%
RCME = 520
VCME = slow
CAR=W26S10
PCME = 15%
RCME = 500
VCME = slow

4. CME Probabilistic Model CME Initial Parameters
CAR=E40S10
PCME = 16%
RCME = 470
Run 1
V=1000 km/s
R = 200
Run 2
V=1000 km/s
R = 400
Run 3
V=1000 km/s
R = 600
Run 4
V=1500 km/s
R = 200
Run 5
V=1500 km/s
R = 400
Run 6
V=1500 km/s
R = 600
Run 7
V=2000 km/s
R = 200
Run 8
V=2000 km/s
R = 400
Run 9
V=2000 km/s
R = 600

5. CME Initial Parameters ICME Propagation

6. ICME Propagation Ensemble Study
RUN 1: V = 1000 km/s, R = 200
RUN 2: V = 1000 km/s, R = 400
RUN 3: V = 1000 km/s, R = 600
RUN 4: V = 1500 km/s, R = 200
RUN 5: V = 1500 km/s, R = 400
RUN 6: V = 1500 km/s, R = 600
RUN 7: V = 2000 km/s, R = 200
RUN 8: V = 2000 km/s, R = 400
RUN 9: V = 2000 km/s, R = 600

7. “External” Bz Periods – Shock Compression
Shock to north, positive IMF: +
Shock to north, negative IMF: -
Shock to south, positive IMF: -
Shock to south, negative IMF: +

8. “External” Bz Periods – ICME Draping
Above ICME center, positive IMF: - +
Above ICME center, negative IMF: + -
Below ICME center, positive IMF: + -
Below ICME center, negative IMF: - +

9. Flux-Rope-Like Structure – Hydrodynamic

10. Flux-Rope-Like Structure – With 2D Magnetic Field

11. Configuration of Magnetic Flux-Ropes
(Bothmer and Schwenn, 1998)
Magnetic cloud properties can be related to observed filament structure

12. Flux-Rope at Earth
Magnetic flux rope is described by analytic force-free (Lundquist) model.
Temporal profiles within the traced ejecta are replaced by that solution.

13. Configuration of Magnetic Flux-Ropes
(Yurchyshyn, 2006)
For about 60% of events the halo elongations and the MC orientation correspond the local tilt of the HCS
For majority of solar ejecta (80%), the underlying erupting flux rope at 1 AU aligns itself with the HCS

14. Halo CME Event

15. AR 10759 – Magnetic Eruption Probability

16. AR 10759 – Maximum CME Speed and Width

17. CME Initial Parameters ICME Propagation

18. CME Initial Parameters ICME Propagation

19. Prediction of the Probability of the Bz Event
Shock strength varies slightly in time due to its large angular extension
Bz impact is narrower and it is stronger at the flux-rope axis

20. Conclusions
Predicting CME impact before magnetic eruption happens (increasing lead time from 1-3 days to 3-5 days) is challenging, crude estimations might be possible, mostly for all-clear conditions.
“Cone” model is a hydrodynamic ejecta and cannot predict Bz events. Inclusion of analytic profiles is the way for event-by-event predictions.
Inclusion of analytic profiles of the magnetic structure helps to narrow the spatial extent of the strongest impact.
More work is needed to calibrate empirical and statistical relationships on onset time, speed, and width.
More work is needed to develop the “hybrid” modeling of Bz events at Earth and calibrate the flux-rope parameters especially at flanks.