Magnetic Topology of the 29 October 2003 X10 Flare MSU Solar Physics Group Angela Des Jardins1, Richard Canfield1, Dana Longcope1, Scott Waitukaitis2 1Physics Dept., Montana State University 2Physics Dept., University of Arizona Introduction Observational Results In order to improve the understanding of both flare initiation and evolution, we take advantage of powerful new topological methods and the high spatial resolution of RHESSI to examine where magnetic reconnection takes place in flare-producing solar active regions. Up to this time, such studies have been carried out on a very small number of active regions. We use the powerful X10 flare on 29 October 2003 as a test of the ability to interpret the topological location of reconnection. We find a relationship between the spine lines and the temporal evolution of the HXR flare footpoints. In this poster, we present observations supporting the relationship and survey possible interpretations. Figure 5. Flux time profiles of the two 50 - 300 keV sources. The ‘large’ source is the left source in Fig. 6 and the ‘small’ source is the right. Figure 6. RHESSI centroid locations, plotted every 4s from 20:47 (red) - 20:57 (white) UT for the left (brighter) footpoint source, and plotted every 20s from 20:49 (red) - 20:57 (white) UT for the right footpoint source, over a MDI magnetogram. Average standard deviation of the centroid locations is 2.4”. Figure 7. Topology terminology: Fan field lines from nulls B2 and A4 in the upper half-space z > 0. The lower half-space is a mirror reflection of this. The fan from A4 (green) is unbroken—all field lines go to P1. The fan from B2 consists of two sectors, one going to N4 (blue) and the other to N6 (red). One separator, going to A3 (magenta), divides these sectors above the plane; a second separator is a mirror image of this below z = 0. The spines from A3 are shown in cyan. (Longcope and Klapper 2002) Observations Figure 1. GOES light curve of the 29 October flare. The two MDI magnetograms used here were recorded prior to (20:30 UT) and during (20:53 UT) the flare and are labeled P/D. The period over which the flare footpoints are observed to separate from one another (20:47-20:57 UT) is shaded in tan and labeled S. P D S Figure 2. RHESSI light curve of the 29 October flare. Figure 9. MPOLE footprint: solid green lines are spine lines, dashed lines are the intersections of the fan surfaces at the photosphere, poles are labeled as in Fig. 6, and the triangles are null points. The + symbols are as in Fig. 6 and 8. Figure 8. TRACE 195 Å image at 20:50:42 UT and MPOLE spine lines from the P magentogram. The + symbols are the same as in Fig. 6. Figure 3. MDI magnetogram of AR 10486 at time P with contours of RHESSI images at 20:50:36 UT. All contours are 50% of max; blue = 18 - 25 keV, green = 25 - 50 keV, red = 50 - 100 keV. The black box is the FOV for Fig. 4. Figure 4. RHESSI 50 - 100 keV image at 20:50:36, rotated to time P, with MPOLE regions (green and yellow contours), and poles (‘P01a’: ‘P’ - positive region, ‘01’ - strongest source in the image area, ‘a’ - is one of 3 poles in the P01 source). Black lines are examples of MPOLE field lines which connect the positive pole P01b to negative poles N07a, N12c, N10a, and N10c. Flare location near the central meridian (80”, 275”) provides ideal magnetogram data for our study on the topological location of magnetic reconnection. Figure 10. - MDI magnetogram with RHESSI contours of the image in Fig. 4 (50%, black), + symbols as in Fig. 6, 8 and 9, and the separators connecting nulls in the vicinity of the RHESSI HXR sources. References Conclusions In this flare study, we use the MPOLE software to extrapolate from the photospheric magnetic field, as observed by MDI, to a coronal field. MPOLE is a suite of IDL programs implementing the Minimum Current Corona Model (Longcope 1996); it currently includes a new method that uses a hierarchy of topological features (Beveridge 2006) to enhance the realism of the extrapolation. The extrapolation gives the location of topological features such as poles, nulls, separatricies, separators, and spine lines. We examine the flare emission observed by RHESSI in the context of these topological features. A magnetic model created by MPOLE reveals the existence of several candidates for reconnection (separators). The separator shown in purple in Fig. 10 coincides with the observed high energy RHESSI emissions. The spreading motions of the footpoints along the spine lines is fully consistent with upward motion of the separator. Beveridge, C. and Longcope, D.W. 2006, ApJ, 636, 453 Longcope, D.W. 1996, Sol. Phys. 169,91 Longcope, D.W. and Klapper, I. 2002, ApJ, 579, 468