1. Dec 9, 2005AGU Fall 2005, San Francisco Reconnection in the Solar Corona Probing the fundamental scales Dana Longcope Montana State University Work supported by NASA, NSF & DoD Thanks: Mark Linton, NRL

2. Dec 9, 2005AGU Fall 2005, San Francisco Driver: Photospheric Field 00:0012:0000:0012:00 Aug 10, 2001 Aug 11, 2001 00:00 MDI TRACE 171A 7:34 AR9574 AR9570 movie Emergence: (Longcope et al. 2005)

3. Dec 9, 2005AGU Fall 2005, San Francisco Coronal Response Potential field: minimum energy state 0 W pot W y (v) Flux y (v) interconn- ects new & old Ars increases - emerg’ce

4. Dec 9, 2005AGU Fall 2005, San Francisco Estimating Coronal Response Constrain interconnecting flux  0 W fce W pot W DWDWDWDW I = 1.3 x 10 11 Amps y (v)  ~ const.  y  y (v) =10 21 Mx Minimum energy: FCE Reconn. dormant

5. Dec 9, 2005AGU Fall 2005, San Francisco Equilibrium Current Sheet… Far from CS: …gross structure determined by p-spheric field

6. Dec 9, 2005AGU Fall 2005, San Francisco Quasi-static Evolution  I=88 GAI=42 GA I=5 GA No recon’ion

7. Dec 9, 2005AGU Fall 2005, San Francisco Internal CS Structure… *   … set by non-ideal effects* Sweet-Parker Reconnection outflows ~ 50 Mm = 4 months

8. Dec 9, 2005AGU Fall 2005, San Francisco InstabilitiesInstabilities   Unstable: Unstable:  > 2   > 2  1. Resistive Tearing 1. Resistive Tearing (Furth et al. 1963)

9. Dec 9, 2005AGU Fall 2005, San Francisco InstabilitiesInstabilities 1. Resistive Tearing 1. Resistive Tearing (Furth et al. 1963) Stabilizing effects: Stabilizing effects: Sweet-Parker flow (Phan & Sonnerup 1991) Sweet-Parker flow (Phan & Sonnerup 1991) Para’ll comp. of B (3 rd dimension) Para’ll comp. of B (3 rd dimension) Nonlinear saturation (turbulence) Nonlinear saturation (turbulence) Instab. enhances diffusion … drives CS to marginal stability  ~ 1000 Instab. enhances diffusion … drives CS to marginal stability  ~ 1000

10. Dec 9, 2005AGU Fall 2005, San Francisco c/ w pi riririri 

11. Dec 9, 2005AGU Fall 2005, San Francisco ReconnectionReconnection Biernat et al. 1987 Localized in space & time Localized in space & time Fast rec’n w/ slow shocks Fast rec’n w/ slow shocks Creates reconnected loops  Creates reconnected loops  New CS forms in wake New CS forms in wake 2d

12. Dec 9, 2005AGU Fall 2005, San Francisco ReconnectionReconnection Linton & Longcope 2006 3d Localized in space & time Localized in space & time Fast rec’n w/ slow shocks Fast rec’n w/ slow shocks Creates reconnected loops  Creates reconnected loops  New CS forms in wake New CS forms in wake

13. Dec 9, 2005AGU Fall 2005, San Francisco Reconnection Observed reconnected loops  Q: How do loop diameters relate to ReX size? TRACE 171A

14. Dec 9, 2005AGU Fall 2005, San Francisco Reconnection Observed reconnected loops  Q: How do loop diameters relate to ReX size? A: Not Simply

15. Dec 9, 2005AGU Fall 2005, San Francisco c/ w pi riririri RAM TRACE

16. Dec 9, 2005AGU Fall 2005, San Francisco Summary: Current Sheets Global structure:Global structure: Set by p-spheric field Set by p-spheric field can be estimated today (~ 30 Mm) can be estimated today (~ 30 Mm) Internal structure:Internal structure: set by non-ideal effects (i.e.  ) set by non-ideal effects (i.e.  ) reconnection: will occur onreconnection: will occur on internal scales - creating loops internal scales - creating loops Cannot (yet) observed these scalesCannot (yet) observed these scales Estimate: < 30 kmEstimate: < 30 km