1. NLFFF Extrapolation for AR 10486 J.McTiernan

2. *Chromospheric* Vector Magnetogram of AR 10486 (from Tom Metcalf) 18:46 UT Image is of Line of sight B (B z ) Contours are RHESSI images, 6-12 keV, 25-50 keV from 20:42:20 UT to 20:44:00 UT

4. Optimization method: Wheatland, Sturrock, Roumeliotis, 2000 Apj, 540, 1150

5. Optimization method (cont): Iterative process, start with Potential or linear FF field, extrapolated from magnetogram. (We prefer the potential field, since we expect the field to be potential far from the active region.) Be sure that B does not change on the boundary Calculate F, set new B = B + F*dt “Objective function”, L, is guaranteed to decrease, but the change in L (dL) becomes smaller as you go. Keep going until dL approaches 0.

8. http://sprg.ssl.berkeley.edu/~krucker/oct29.html

10. Conclusions:  Left hand FP moves along feature seen in Magnetogram, not sure about Right FP  Hard to see connectivity  Currently processing photospheric magnetograms.

11. 29-Oct-2003 (cont.) Early phase: only low- energy emission

12. 29-Oct-2003 (cont.) Low energy source (thermal? looptop?) in between HXR footpoints.

13. 29-Oct-2003 (cont.) Note that the footpoints have moved. The loop arcade is visible in 195A which has some high T response.