1. SHINE 2006 David Alexander Rice University Exploring the dynamics of flux-emergence in magnetically-complex solar active regions David Alexander and Lirong Tian Rice University

2. SHINE 2006 David Alexander Rice University Twist and writhe in  -configuration active regions Tian et al., Sol. Phys., 229, 63, 2005a Systematic tilt ≡ writhe  best ≡ twist

3. SHINE 2006 David Alexander Rice University Twist and writhe in  -configuration active regions Tian et al., Sol. Phys., 229, 63, 2005a These results support the idea of a kink instability driving the active region evolution: - writhe and twist have same sign (via helicity conservation) a la models by Linton, Fan and others Models can also yield  -configurations without kinking Observations also ‘require’ ARs in QII and QIV emerge with high initial twist Both HNJL and HHR are followed by most active regions with simple bipolar (non-δ) magnetic configuration. These ARs have twist of the opposite sign to the writhe (see quadrant I in Figure 2). Only about 20% of  ARs adhere to both HNJL and HHR For active regions with complex (δ) magnetic configurations, about 34% violate HNJL, but follow HHR, while 32% follow HNJL, but violate HHR. Of the 104 active regions 65–67% have the same sign of the twist and writhe (see quadrants II and IV in Figure 1). Non-Hale or non-HHR  ARs produce more large flares (but not exclusively).

4. SHINE 2006 David Alexander Rice University Long-term evolution of active regions: role of kink instability Tian et al., Sol. Phys., 229, 237, 2005b Expect left-handed writhe in South

5. SHINE 2006 David Alexander Rice University Long-term evolution of active regions: role of kink instability Tian et al., Sol. Phys., 229, 237, 2005b Non-Hale region Clockwise rotating filaments

6. SHINE 2006 David Alexander Rice University Long-term evolution of active regions: role of kink instability Tian et al., Sol. Phys., 229, 237, 2005b Sunspot-group shows pronounced clockwise rotation: - 8 o -10 o per day, 220 o -270 o per solar rotation Filaments also show clockwise rotation Clockwise rotation was long-lasting (four solar rotations) Positive twist indicates right-handed twist, positive tilts indicates right-handed writhe. Again, these results support the idea of a kink instability driving the active region evolution. AR must result from a fluxtube with large positive twist with helicity transfer to writhe generating clockwise rotation.

7. SHINE 2006 David Alexander Rice University Sunspot and sunspot-group rotation: driving sigmoidal activity Tian & Alexander, Sol. Phys., 233, 29, 2006 Relation of sunspot rotation to sunspot-group rotation to generation of free energy in the corona via connection between twist and writhe. Large leading spot rotates counter-clockwise. Spot-group rotates counter-clockwise

8. SHINE 2006 David Alexander Rice University Sunspot and sunspot-group rotation: driving sigmoidal activity Tian & Alexander, Sol. Phys., 233, 29, 2006 Vector B Vertical current Vertical current helicity Polarity separation Systematic tilt h z = (  B) z  B z =  J z B z Tilt angle positive prior to Oct 30 and negative thereafter - right-left handed writhe -  W<0 Dominant negative current is distributed within positive polarity sunspot which rotated counter-clockwise.

9. SHINE 2006 David Alexander Rice University Sunspot and sunspot-group rotation: driving sigmoidal activity Tian & Alexander, Sol. Phys., 233, 29, 2006 Filament and sigmoid also rotated counter-clockwise, consistent with magnetic and current systems. Sunspot and sunspot-group rotation played an important role in the formation and eventual eruption of coronal sigmoid. Decrease in writhe implies increase in twist implying additional positive twist being added to active region which should show up as a clockwise rotation. So continued negative twist must be produced by some other mechanism. Magnetic field also grows more complex with time suggestion increasing magnitude of twist – opposite observations.

10. SHINE 2006 David Alexander Rice University Origins of coronal helicity: AR10030 Tian, Alexander & NIghtingale, ApJ, submitted SP2 - strong anti-clockwise rotation, no emergence SP4 – strong emergence, some anti-clockwise rotation

11. SHINE 2006 David Alexander Rice University Origins of coronal helicity: AR10030 Tian, Alexander & NIghtingale, ApJ, submitted SP4 SP2 Vector B Vertical current Both show significant growth in current density SP2 associated with sigmoid formation, 5 M-class and 1 X-class flares. SP4 associated with sigmoid formation, and flaring activity. Rotation speed Mean current Magnetic flux

12. SHINE 2006 David Alexander Rice University Bringing it all together Detailed studies of active region magnetic field evolution can  yield insight into the sub-surface dynamics of the parent magnetic fluxtubes  delineate magnetic complexity –  -configurations, fragmentation, non-Hale-icity – and provide key to generation of coronal free energy  help determine role of twist and writhe – e.g. sunspot rotation and flux emergence – and role of helicity  provide a link between the dynamics of the solar interior and the driving of eruptive coronal phenomena The kink instability seems to be an important process in flare/CME productive active regions

13. SHINE 2006 David Alexander Rice University Future Work  Incorporate better vector magnetic field data into the analysis (Solar-B)  Apply more realistic velocity/field coupling (inductive equation?)  Combine modeling with observation (HAO/Rice collaboration)  Emergence of asymmetric fluxtubes  Driving of solar eruptive phenomena