Babcock-Leighton Dynamo Theory and Solar Cycle #24 Kenneth Schatten Ai-solutions

OUTLINE SA PRED: FEEL+ TO PHYS. MODELS: DIKPATI +. PRECURSORS PREDS.: GEOMAGNETIC & SOLAR BABCOCK – LEIGHTON DYNAMO THE SUN’S POLAR FIELD PREDICTION FOR CYCLE #24 ?s FOR MODELS PREDICTING LARGE CYCLE#24 SUMMARY AND CONCLUSIONS

SOLAR ACTIVITY

Geomagnetic Precursors, Kane

Solar Precursors : Brief Theory General dynamo theory – DISK DYNAMO Solar Babcock-Leighton model Solar Dynamo Method - Magnetic fields at the Sun’s Poles are the precursors for future active region fields. Near Solar Minimum, the Polar field of the Sun extends past the Earth. This affects geomagnetic activity: hence geomag precursors may serve to predict the Sun’s activity.

General Dynamo Theory –DISK DYNAMO (MHD – FIELDS AMPLIFY PRE-EXISTING FIELD)

Babcock-Leighton model

Traditional Solar Physics Hale’s Laws Spoerer Butterfly Diagram Joy’s Law

How the Sun ‘Broadcasts’ the State of its Internal Mag. Field 2 STEPS: STEP 1: Polar field at solar minimum acts as a precursor for the toroidal field (active regions).

How the Sun ‘Broadcasts’ the State of its Internal Mag. Field STEP 2: Near solar min., the solar wind extends the polar field into the interplanetary field. When it dips low enough to reach the ecliptic it can affect geomag. activity. This allows it to serve as a precursor for next cycle’s activity. Shown are the computed field lines on top of structure of the eclipse of Nov. 12, 1966. Schatten, K.H., “Current Sheet Magnetic Model for the Solar Corona," Cosmic Electrodynamics, 11, 4, Asilomar Conference on the Solar Wind, (1971).

The Sun’s Polar Field We often use a “SODA (Solar Dynamo Amplitude) Index, which incorporates the Sun’s Toroidal and Poloidal Fields, but to reduce complexity are showing the polar fields alone, as these have less “active region noise.”

F10.7 Observations and Predictions

Where did the Sun’s Field go? Present Coronal Holes ‘Normal’ Polar Coronal Holes at Solar Minimum Idealized Model of “Typical” Solar Minimum Corona Yohkoh Soft X-ray Image Aug. 1996 2005 October, 1996 Coronal Hole Drawing, Karen Harvey, using Kitt Peak He 10830 line April, May, 2005 STAR SOHO/MDI Coronal Hole Map

?s FOR MODELS PREDICTING LARGE CYCLE #24 DIKPATI + MODEL: FEEL + TOWARDS PHYS. MODELS, BUT SOME ?s ARISE:1) DATA ANALYSIS ? ,2) WHY SHOULD FLOW FOLLOW THEIR PARTICULAR PATTERN? WHAT EXPLAINS THE OBSERVED DOWNTURN IN THE SUN’S POLAR FIELD FOR THE LAST SEVERAL YEARS? THE POLAR FIELD & ITS PROXIES (e.g. POLAR FACULAE) CORRELATE WELL WITH THE NEXT CYCLE’S ACTIVITY. WHAT EXPLAINS THIS (IF NOT THE B-L MODEL)?

SUMMARY/CONCLUSIONS BABCOCK-LEIGHTON DYNAMO THEORY POLAR FIELD (OR PROXY) IS PRECURSOR FOR NEXT CYCLE’S ACTIVITY CURRENTLY POLAR FIELD IS LOW THEREFORE, IF B-L THEORY & OUR INTERPRETATION OF IT IS RIGHT, CYCLE #24 WILL BE LOW