The Topology of Magnetic Reconnection in Solar Flares

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4troscopy to determine the thermal and nonthermal features of a flare. Figure 1.2 shows aRHESSI count flux spectra (counts cm -2 s -1 keV -1 ) of the impulsive phase (~22:55-23:05)of the 4 November 2004. The 3 to 20 keV range of the spectrum is dominated by thermal(blackbody) radiation. This SXR/HXR emission has a temperature of 10 to 20 MK and isemitted by hot plasma that fills the flare loop. Due to the strong magnetic field and the lowthermal pressure, the shape of flare loops are determined by the shape of the loop’s magneticfield lines. Other thermal emission is observed in the chromosphere (Hα and UV) atthe base of flare loops and in the corona (EUV) in cooler, ~1 MK post flare loops.Above 20-30 keV, flare spectra are dominated by nonthermal emission, which can becharacterized by a power-law. Nonthermal emission is typically observed in HXR, UV andHα at the base of flare loops (footpoint sources).In some flares, especially large flares associated with coronal mass ejections (CMEs),the brightening in Hα and UV is not concentrated in a single source, but has two extendedsources, or ribbons, that separate as the flare progresses. In an effort to explain this commonlyobserved phenomenon in terms of the physical mechanism that releases the energystored in flaring active region magnetic fields, the CSHKP model (Carmichael, 1964; Sturrock,1968; Hirayama, 1974; Kopp and Pneuman, 1976), now refered to as the standardmodel of solar flares, was developed.The CSHKP model, shown in Figure 1.3, is a 2D model that describes how stressedmagnetic field lines are pushed together such that they form a current sheet at the X-point,where field lines from the sides of the configuration are reconnected (see e.g. Priest andForbes, 2000) to form new field lines above (open) and below (closed) the reconnectionregion. In the CSHKP model, the reconnection region is refered to as an X-point becausethis is the shape made by the intersection of the separatrix surfaces in 2D. A separatrix is asurface that divides magnetic field lines into regions of different connectivity.Magnetic reconnection is commonly accepted as the way stressed coronal magnetic
5100.000RHESSI Count Flux vs Energy4-Nov-2004Detectors: 1F 3F 4F 5F 6F 8F 9F22:55:00.000 - 23:05:00.00010.0001.0000.1000.0100.00110 100Energy (keV)25 Jun 2007 13 48Figure 1.2: Top: RHESSI spectrum (in counts cm -2 s -1 keV -1 ) from the impulsive phase(22:55 - 23:05 UT) of the 4 November 2004 flare. Bottom: RHESSI 6-12 keV image with25-50 keV contours (drawn at 70% of the maximum) summed over the same time periodas the spectrum.
Page 1 and 2: THE TOPOLOGY OF MAGNETIC RECONNECTI
Page 3 and 4: iiAPPROVALof a dissertation submitt
Page 5: ivTo Liebe -I’m the lucky one
Page 8 and 9: viiLIST OF TABLESTablePage2.1 Flare
Page 10 and 11: ix2.3 Left hand panels are GOES lig
Page 12 and 13: xiABSTRACTIn order to better unders
Page 14: 2The release of this large amount o
Page 19 and 20: 7excitation in the chromosphere.The
Page 21 and 22: 9one day before the two large X-cla
Page 23 and 24: 11of well-defined features like sun
Page 25 and 26: 13introduced (i.e. Titov et al., 20
Page 27 and 28: 15CHAPTER 2RECONNECTION IN THREE DI
Page 29 and 30: 17spine lines.In this Chapter, for
Page 31 and 32: 19Table 2.1: Flare properties. AR i
Page 33 and 34: 21-300A) TRACE 195, RHESSI 50-100 k
Page 35 and 36: 23Figure 2.3: Left hand panels are
Page 37 and 38: 25the same time. With a 20 s imagin
Page 39 and 40: 27sheared or twisted flux tubes, wh
Page 41 and 42: 29Figure 2.4: Top: photospheric foo
Page 43 and 44: 31track 2 to 3 and from track 3 to
Page 45 and 46: 33error. If we had simply fit the f
Page 47 and 48: 3512 23 31Figure 2.6: Upper panel:
Page 49 and 50: 37In case 1, we suppose that the do
Page 51 and 52: 39null which shifts during the flar
Page 53 and 54: 41tiation and evolution. Further wo
Page 55 and 56: 43photospheric and coronal magnetic
Page 57 and 58: 45Here, B z (x,y) is the value of t
Page 59 and 60: 47been determined, several other to
Page 61 and 62: 49Figure 3.1: Simulated magnetogram
Page 63 and 64: 51Figure 3.3: Same as Figure 3.1, b
Page 65 and 66:
53MDI 6 Apr 2004, 12:51 UT-120-140-
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55of new field and horizontal flows
Page 69 and 70:
57arators (Henoux and Somov, 1987).
Page 71 and 72:
59the line-tied nature of the photo
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61a snapshot in time (Démoulin, 20
Page 75 and 76:
63Figure 4.1: GOES and RHESSI light
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65order to take advantage of the av
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67field lines or sheared or twisted
Page 81 and 82:
69Flare A, MDI 01:39 UT400438350256
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71flux discrepancy∆Φ r = −∆t
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73Flare A, RHESSI 30-100 keV4004383
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75(in the form of heating and parti
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77CHAPTER 5DISCUSSION AND CONCLUSIO
Page 91 and 92:
79separator (nulls) are along spine
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81emission is concentrated in compa
Page 95 and 96:
83REFERENCESAulanier, G., P. Démou
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85Meyer, S. J. Morrison, M. D. Morr
Page 99 and 100:
87Priest, E., and T. Forbes, Magnet
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The Topology of Magnetic Reconnection in Solar Flares

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