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How to measure the magnetic reconnection rate of two-ribbon solar flares

How to measure the magnetic reconnection rate of two-ribbon solar flares. Ju Jing 2007 Nov.2. Solar flares are often classified into two types: compact flares and two-ribbon flares. Two-ribbon flares tend to be larger more energetic more likely to be associated with an eruption.

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How to measure the magnetic reconnection rate of two-ribbon solar flares

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  1. How to measure the magnetic reconnection rate of two-ribbon solar flares Ju Jing 2007 Nov.2

  2. Solar flares are often classified into two types: compact flares and two-ribbon flares • Two-ribbon flares tend to be • larger • more energetic • more likely to be associated with an eruption Two-ribbon flare of 2000 Sept. 12

  3. The physical link between flares and eruptions is magnetic reconnection. Magnetic reconnection Magnetic reconnection Ribbon (Courtesy of Terry Forbes )

  4. How to measure the magnetic reconnection rate (Forbes and Priest 1984, Forbes and Lin 2000) Electric Field in the reconnecting current sheet (RCS) Magnetic Flux Change Rate Or voltage drop along a separator line rec = Vr Bn dl Erec = Vr Bn Assumption 1 Assumption 2 Assumption 1: Neither the length of the ribbons l nor the Bn changes with time significantly. Assumption 2: There is a translational symmetry along the ribbon, i.e., in a two-dimensional configuration. Where Vris the ribbon separation velocity; l is length along the RCS ; dA is the newly brightened area swept by flare ribbons; Bn is the normal component of the magnetic field strength.

  5. A massive two-ribbon flare of 2006 Dec. 13 A two-ribbon flare occurred in active region NOAA 10930 on 13 December 2006 and was captured by Solar Optical Telescope (SOT) on board Hinode.

  6. A massive flare of 2006 Dec. 13 Large Angle and Spectrometric Coronagraph (LASCO) C2 coronagraph movie TRACE 195 A movie

  7. The spatial distribution of Bn, Vr, VrBn and VrBn2 along the index j1=50-115 (left panel) and j2=0-50 (right panel). The grey bars indicate the locations of two G-band kernels in accordance with the j1 and j2.

  8. The temporal evolution of VrBn(red) and rec(black).

  9. The magnetic reconnection rate may be derived from flare observations using sound assumptions and approximations, i.e., it can be deduced by measuring the expansion offlare ribbons across the magnetic fields.

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