70 likes | 201 Views
Changes of Magnetic Structure in 3-D Associated with Major Flares. X3.4 flare of 2006 December 13 (J. Jing, T. Wiegelmann, Y. Suematsu M.Kubo, and H. Wang, 2008 ApJL, 676, L81) X 5.3 flare of 2001 August 25 (in preparation) X1.6 flare of 2001 October 19 (in preparation) ….
E N D
Changes of Magnetic Structure in 3-D Associated with Major Flares • X3.4 flare of 2006 December 13 • (J. Jing, T. Wiegelmann, Y. Suematsu M.Kubo, and H. Wang, 2008 ApJL, 676, L81) • X 5.3 flare of 2001 August 25 (in preparation) • X1.6 flare of 2001 October 19 (in preparation) • …
Background and Motivation • Rapid and permanent changes of photosphere magnetic fields associated with solar flares have been reported in at least 16 publications during the past eight years (e.g., Cameron & Sammis 1999; Wang et al. 2002; Spirock et al. 2002; Meunier & Kosovichev 2003; Yurchyshyn et al. 2004; Deng et al. 2005; Liu et al. 2005; Sudol & Harvey 2005, etc.; Chen et al. 2007) • the unbalanced magnetic flux • the increase in transverse magnetic fields • penumbral decay and central feature enhancement • the decrease or increase in magnetic shear near the flaring neutral line • 3-D magnetic structure and its evolution will provide key understanding of this subject.
Data Sets Hinode SP vector magnetograms (FOV: ~300”160”; Resolution: ~0.2”/pixel) • advantages: seeing–free, high-resolution, high-precision • disadvantages: poor-cadence BBSO DVMG vector magnetograms (FOV: ~350”350”; Resolution: ~0.6”/pexel) • advantages: high cadence, ~1 min • disadvantages: seeing problem, Zeeman saturation *SDO Helioseismic and Magnetic Imager (HMI) vector magnetograms (FOV: full disk; Resolution: ~1”/pixel; Cadence: ~90 s) 180-degree Ambiguity Resolving Tools theMinimum Energy algorithm by Metcalf (1994) NLFFF Modeling Tools the Optimization algorithm implemented by Wiegelmann (2004)
X3.4 flare of 2006 December 13 AR#: NOAA 10930 Location: S06W35 Flare non-thermal emission peak time: 2006 December 13, 02:28 UT
Data Set: Hinode vector magnetograms taken in two time bins time bin 1 (before the flare): 2006 December 12, 20:30 UT 21:33 UT time bin 2 (after the flare): 2006 December 13, 04:30 UT 05:36 UT Modeling of Coronal Magnetic Fields Potential Fields: Green’s function method – by Tom Metcalf NLFF Fields: optimization method – by Thomas Wiegelmann Magnetic Shear Parameters: Magnetic shear: At each altitude, Weighted mean shear: Total magnetic shear: Where Bi=|Bi| at each pixel i, and the superscripts N and p represent the NLFF field and the potential field, respectively. The sum is performed over all the pixels in a region.
Left: Line-of-sight magnetograms taken before (top) and after (bottom) the flare. The FOV is 140”140”. The rectangles P mark the area close to the flaring magnetic polarity inversion line. Right: weighted mean shear w (top) and total magnetic shear wB (bottom) of area P as a function of altitude for two time bins. The step size of altitude is ~0.46 Mm.
Saturation-free magnetograms Saturated magnetograms NLFF fields NLFF fields Future work: • Learn to extrapolate the NLFF fields • Test the impact of Zeeman saturation on the NLFFF extrapolation • Study the evolution of 3-D magnetic fields during Flares • the electric current system from photosphere to corona • the evolution of magnetic free energy • the evolution of magnetic field lines in peripheral penumbra • compare the observational findings with theoretical models