A Method for Estimating the Spatial Period of Energy Release in Solar Flares II

The method for estimating the spatial period of energy release in solar flares based on the application of a Fourier analysis to the difference images of flare arcades in the far ultraviolet is applied to the observations of the large solar flare on November 4, 2003. The flare occurred at the solar limb; the flare arcade extending along the solar limb was imaged in detail in the ultraviolet 195 Å channel of the TRACE satellite. The Fourier analysis of its difference images has shown the presence of a series of harmonics in the spatial distribution of the regions of flare energy release with characteristic periods lying in the range from 3.3 to 18.6 Mm. Such periodization may result from the decay of the preflare current layer accumulating the solar flare energy in coronal magnetic fields due to some instability of thermal, plasma, or other nature.